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citra/src/video_core/rasterizer.cpp

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// Copyright 2014 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <algorithm>
#include "common/common_types.h"
#include "common/math_util.h"
#include "common/profiler.h"
#include "core/hw/gpu.h"
#include "core/memory.h"
#include "debug_utils/debug_utils.h"
#include "math.h"
#include "color.h"
#include "pica.h"
#include "rasterizer.h"
#include "vertex_shader.h"
#include "video_core/utils.h"
namespace Pica {
namespace Rasterizer {
static void DrawPixel(int x, int y, const Math::Vec4<u8>& color) {
const auto& framebuffer = g_state.regs.framebuffer;
const PAddr addr = framebuffer.GetColorBufferPhysicalAddress();
// Similarly to textures, the render framebuffer is laid out from bottom to top, too.
// NOTE: The framebuffer height register contains the actual FB height minus one.
y = framebuffer.height - y;
const u32 coarse_y = y & ~7;
u32 bytes_per_pixel = GPU::Regs::BytesPerPixel(GPU::Regs::PixelFormat(framebuffer.color_format.Value()));
u32 dst_offset = VideoCore::GetMortonOffset(x, y, bytes_per_pixel) + coarse_y * framebuffer.width * bytes_per_pixel;
u8* dst_pixel = Memory::GetPhysicalPointer(addr) + dst_offset;
switch (framebuffer.color_format) {
case Regs::ColorFormat::RGBA8:
Color::EncodeRGBA8(color, dst_pixel);
break;
case Regs::ColorFormat::RGB8:
Color::EncodeRGB8(color, dst_pixel);
break;
case Regs::ColorFormat::RGB5A1:
Color::EncodeRGB5A1(color, dst_pixel);
break;
case Regs::ColorFormat::RGB565:
Color::EncodeRGB565(color, dst_pixel);
break;
case Regs::ColorFormat::RGBA4:
Color::EncodeRGBA4(color, dst_pixel);
break;
default:
LOG_CRITICAL(Render_Software, "Unknown framebuffer color format %x", framebuffer.color_format.Value());
UNIMPLEMENTED();
}
}
static const Math::Vec4<u8> GetPixel(int x, int y) {
const auto& framebuffer = g_state.regs.framebuffer;
const PAddr addr = framebuffer.GetColorBufferPhysicalAddress();
y = framebuffer.height - y;
const u32 coarse_y = y & ~7;
u32 bytes_per_pixel = GPU::Regs::BytesPerPixel(GPU::Regs::PixelFormat(framebuffer.color_format.Value()));
u32 src_offset = VideoCore::GetMortonOffset(x, y, bytes_per_pixel) + coarse_y * framebuffer.width * bytes_per_pixel;
u8* src_pixel = Memory::GetPhysicalPointer(addr) + src_offset;
switch (framebuffer.color_format) {
case Regs::ColorFormat::RGBA8:
return Color::DecodeRGBA8(src_pixel);
case Regs::ColorFormat::RGB8:
return Color::DecodeRGB8(src_pixel);
case Regs::ColorFormat::RGB5A1:
return Color::DecodeRGB5A1(src_pixel);
case Regs::ColorFormat::RGB565:
return Color::DecodeRGB565(src_pixel);
case Regs::ColorFormat::RGBA4:
return Color::DecodeRGBA4(src_pixel);
default:
LOG_CRITICAL(Render_Software, "Unknown framebuffer color format %x", framebuffer.color_format.Value());
UNIMPLEMENTED();
}
return {0, 0, 0, 0};
}
static u32 GetDepth(int x, int y) {
const auto& framebuffer = g_state.regs.framebuffer;
const PAddr addr = framebuffer.GetDepthBufferPhysicalAddress();
u8* depth_buffer = Memory::GetPhysicalPointer(addr);
y = framebuffer.height - y;
const u32 coarse_y = y & ~7;
u32 bytes_per_pixel = Regs::BytesPerDepthPixel(framebuffer.depth_format);
u32 stride = framebuffer.width * bytes_per_pixel;
u32 src_offset = VideoCore::GetMortonOffset(x, y, bytes_per_pixel) + coarse_y * stride;
u8* src_pixel = depth_buffer + src_offset;
switch (framebuffer.depth_format) {
case Regs::DepthFormat::D16:
return Color::DecodeD16(src_pixel);
case Regs::DepthFormat::D24:
return Color::DecodeD24(src_pixel);
case Regs::DepthFormat::D24S8:
return Color::DecodeD24S8(src_pixel).x;
default:
LOG_CRITICAL(HW_GPU, "Unimplemented depth format %u", framebuffer.depth_format);
UNIMPLEMENTED();
return 0;
}
}
static void SetDepth(int x, int y, u32 value) {
const auto& framebuffer = g_state.regs.framebuffer;
const PAddr addr = framebuffer.GetDepthBufferPhysicalAddress();
u8* depth_buffer = Memory::GetPhysicalPointer(addr);
y = framebuffer.height - y;
const u32 coarse_y = y & ~7;
u32 bytes_per_pixel = Regs::BytesPerDepthPixel(framebuffer.depth_format);
u32 stride = framebuffer.width * bytes_per_pixel;
u32 dst_offset = VideoCore::GetMortonOffset(x, y, bytes_per_pixel) + coarse_y * stride;
u8* dst_pixel = depth_buffer + dst_offset;
switch (framebuffer.depth_format) {
case Regs::DepthFormat::D16:
Color::EncodeD16(value, dst_pixel);
break;
case Regs::DepthFormat::D24:
Color::EncodeD24(value, dst_pixel);
break;
case Regs::DepthFormat::D24S8:
// TODO(Subv): Implement the stencil buffer
Color::EncodeD24S8(value, 0, dst_pixel);
break;
default:
LOG_CRITICAL(HW_GPU, "Unimplemented depth format %u", framebuffer.depth_format);
UNIMPLEMENTED();
break;
}
}
// NOTE: Assuming that rasterizer coordinates are 12.4 fixed-point values
struct Fix12P4 {
Fix12P4() {}
Fix12P4(u16 val) : val(val) {}
static u16 FracMask() { return 0xF; }
static u16 IntMask() { return (u16)~0xF; }
operator u16() const {
return val;
}
bool operator < (const Fix12P4& oth) const {
return (u16)*this < (u16)oth;
}
private:
u16 val;
};
/**
* Calculate signed area of the triangle spanned by the three argument vertices.
* The sign denotes an orientation.
*
* @todo define orientation concretely.
*/
static int SignedArea (const Math::Vec2<Fix12P4>& vtx1,
const Math::Vec2<Fix12P4>& vtx2,
const Math::Vec2<Fix12P4>& vtx3) {
const auto vec1 = Math::MakeVec(vtx2 - vtx1, 0);
const auto vec2 = Math::MakeVec(vtx3 - vtx1, 0);
// TODO: There is a very small chance this will overflow for sizeof(int) == 4
return Math::Cross(vec1, vec2).z;
};
static Common::Profiling::TimingCategory rasterization_category("Rasterization");
/**
* Helper function for ProcessTriangle with the "reversed" flag to allow for implementing
* culling via recursion.
*/
static void ProcessTriangleInternal(const VertexShader::OutputVertex& v0,
const VertexShader::OutputVertex& v1,
const VertexShader::OutputVertex& v2,
bool reversed = false)
{
const auto& regs = g_state.regs;
Common::Profiling::ScopeTimer timer(rasterization_category);
// vertex positions in rasterizer coordinates
static auto FloatToFix = [](float24 flt) {
// TODO: Rounding here is necessary to prevent garbage pixels at
// triangle borders. Is it that the correct solution, though?
return Fix12P4(static_cast<unsigned short>(round(flt.ToFloat32() * 16.0f)));
};
static auto ScreenToRasterizerCoordinates = [](const Math::Vec3<float24>& vec) {
return Math::Vec3<Fix12P4>{FloatToFix(vec.x), FloatToFix(vec.y), FloatToFix(vec.z)};
};
Math::Vec3<Fix12P4> vtxpos[3]{ ScreenToRasterizerCoordinates(v0.screenpos),
ScreenToRasterizerCoordinates(v1.screenpos),
ScreenToRasterizerCoordinates(v2.screenpos) };
if (regs.cull_mode == Regs::CullMode::KeepAll) {
// Make sure we always end up with a triangle wound counter-clockwise
if (!reversed && SignedArea(vtxpos[0].xy(), vtxpos[1].xy(), vtxpos[2].xy()) <= 0) {
ProcessTriangleInternal(v0, v2, v1, true);
return;
}
} else {
if (!reversed && regs.cull_mode == Regs::CullMode::KeepClockWise) {
// Reverse vertex order and use the CCW code path.
ProcessTriangleInternal(v0, v2, v1, true);
return;
}
// Cull away triangles which are wound clockwise.
if (SignedArea(vtxpos[0].xy(), vtxpos[1].xy(), vtxpos[2].xy()) <= 0)
return;
}
// TODO: Proper scissor rect test!
u16 min_x = std::min({vtxpos[0].x, vtxpos[1].x, vtxpos[2].x});
u16 min_y = std::min({vtxpos[0].y, vtxpos[1].y, vtxpos[2].y});
u16 max_x = std::max({vtxpos[0].x, vtxpos[1].x, vtxpos[2].x});
u16 max_y = std::max({vtxpos[0].y, vtxpos[1].y, vtxpos[2].y});
min_x &= Fix12P4::IntMask();
min_y &= Fix12P4::IntMask();
max_x = ((max_x + Fix12P4::FracMask()) & Fix12P4::IntMask());
max_y = ((max_y + Fix12P4::FracMask()) & Fix12P4::IntMask());
// Triangle filling rules: Pixels on the right-sided edge or on flat bottom edges are not
// drawn. Pixels on any other triangle border are drawn. This is implemented with three bias
// values which are added to the barycentric coordinates w0, w1 and w2, respectively.
// NOTE: These are the PSP filling rules. Not sure if the 3DS uses the same ones...
auto IsRightSideOrFlatBottomEdge = [](const Math::Vec2<Fix12P4>& vtx,
const Math::Vec2<Fix12P4>& line1,
const Math::Vec2<Fix12P4>& line2)
{
if (line1.y == line2.y) {
// just check if vertex is above us => bottom line parallel to x-axis
return vtx.y < line1.y;
} else {
// check if vertex is on our left => right side
// TODO: Not sure how likely this is to overflow
return (int)vtx.x < (int)line1.x + ((int)line2.x - (int)line1.x) * ((int)vtx.y - (int)line1.y) / ((int)line2.y - (int)line1.y);
}
};
int bias0 = IsRightSideOrFlatBottomEdge(vtxpos[0].xy(), vtxpos[1].xy(), vtxpos[2].xy()) ? -1 : 0;
int bias1 = IsRightSideOrFlatBottomEdge(vtxpos[1].xy(), vtxpos[2].xy(), vtxpos[0].xy()) ? -1 : 0;
int bias2 = IsRightSideOrFlatBottomEdge(vtxpos[2].xy(), vtxpos[0].xy(), vtxpos[1].xy()) ? -1 : 0;
auto w_inverse = Math::MakeVec(v0.pos.w, v1.pos.w, v2.pos.w);
auto textures = regs.GetTextures();
auto tev_stages = regs.GetTevStages();
// Enter rasterization loop, starting at the center of the topleft bounding box corner.
// TODO: Not sure if looping through x first might be faster
for (u16 y = min_y + 8; y < max_y; y += 0x10) {
for (u16 x = min_x + 8; x < max_x; x += 0x10) {
// Calculate the barycentric coordinates w0, w1 and w2
int w0 = bias0 + SignedArea(vtxpos[1].xy(), vtxpos[2].xy(), {x, y});
int w1 = bias1 + SignedArea(vtxpos[2].xy(), vtxpos[0].xy(), {x, y});
int w2 = bias2 + SignedArea(vtxpos[0].xy(), vtxpos[1].xy(), {x, y});
int wsum = w0 + w1 + w2;
// If current pixel is not covered by the current primitive
if (w0 < 0 || w1 < 0 || w2 < 0)
continue;
auto baricentric_coordinates = Math::MakeVec(float24::FromFloat32(static_cast<float>(w0)),
float24::FromFloat32(static_cast<float>(w1)),
float24::FromFloat32(static_cast<float>(w2)));
float24 interpolated_w_inverse = float24::FromFloat32(1.0f) / Math::Dot(w_inverse, baricentric_coordinates);
// Perspective correct attribute interpolation:
// Attribute values cannot be calculated by simple linear interpolation since
// they are not linear in screen space. For example, when interpolating a
// texture coordinate across two vertices, something simple like
// u = (u0*w0 + u1*w1)/(w0+w1)
// will not work. However, the attribute value divided by the
// clipspace w-coordinate (u/w) and and the inverse w-coordinate (1/w) are linear
// in screenspace. Hence, we can linearly interpolate these two independently and
// calculate the interpolated attribute by dividing the results.
// I.e.
// u_over_w = ((u0/v0.pos.w)*w0 + (u1/v1.pos.w)*w1)/(w0+w1)
// one_over_w = (( 1/v0.pos.w)*w0 + ( 1/v1.pos.w)*w1)/(w0+w1)
// u = u_over_w / one_over_w
//
// The generalization to three vertices is straightforward in baricentric coordinates.
auto GetInterpolatedAttribute = [&](float24 attr0, float24 attr1, float24 attr2) {
auto attr_over_w = Math::MakeVec(attr0, attr1, attr2);
float24 interpolated_attr_over_w = Math::Dot(attr_over_w, baricentric_coordinates);
return interpolated_attr_over_w * interpolated_w_inverse;
};
Math::Vec4<u8> primary_color{
(u8)(GetInterpolatedAttribute(v0.color.r(), v1.color.r(), v2.color.r()).ToFloat32() * 255),
(u8)(GetInterpolatedAttribute(v0.color.g(), v1.color.g(), v2.color.g()).ToFloat32() * 255),
(u8)(GetInterpolatedAttribute(v0.color.b(), v1.color.b(), v2.color.b()).ToFloat32() * 255),
(u8)(GetInterpolatedAttribute(v0.color.a(), v1.color.a(), v2.color.a()).ToFloat32() * 255)
};
Math::Vec2<float24> uv[3];
uv[0].u() = GetInterpolatedAttribute(v0.tc0.u(), v1.tc0.u(), v2.tc0.u());
uv[0].v() = GetInterpolatedAttribute(v0.tc0.v(), v1.tc0.v(), v2.tc0.v());
uv[1].u() = GetInterpolatedAttribute(v0.tc1.u(), v1.tc1.u(), v2.tc1.u());
uv[1].v() = GetInterpolatedAttribute(v0.tc1.v(), v1.tc1.v(), v2.tc1.v());
uv[2].u() = GetInterpolatedAttribute(v0.tc2.u(), v1.tc2.u(), v2.tc2.u());
uv[2].v() = GetInterpolatedAttribute(v0.tc2.v(), v1.tc2.v(), v2.tc2.v());
Math::Vec4<u8> texture_color[3]{};
for (int i = 0; i < 3; ++i) {
const auto& texture = textures[i];
if (!texture.enabled)
continue;
DEBUG_ASSERT(0 != texture.config.address);
int s = (int)(uv[i].u() * float24::FromFloat32(static_cast<float>(texture.config.width))).ToFloat32();
int t = (int)(uv[i].v() * float24::FromFloat32(static_cast<float>(texture.config.height))).ToFloat32();
static auto GetWrappedTexCoord = [](Regs::TextureConfig::WrapMode mode, int val, unsigned size) {
switch (mode) {
case Regs::TextureConfig::ClampToEdge:
val = std::max(val, 0);
val = std::min(val, (int)size - 1);
return val;
case Regs::TextureConfig::Repeat:
return (int)((unsigned)val % size);
case Regs::TextureConfig::MirroredRepeat:
{
unsigned int coord = ((unsigned)val % (2 * size));
if (coord >= size)
coord = 2 * size - 1 - coord;
return (int)coord;
}
default:
LOG_ERROR(HW_GPU, "Unknown texture coordinate wrapping mode %x\n", (int)mode);
UNIMPLEMENTED();
return 0;
}
};
// Textures are laid out from bottom to top, hence we invert the t coordinate.
// NOTE: This may not be the right place for the inversion.
// TODO: Check if this applies to ETC textures, too.
s = GetWrappedTexCoord(texture.config.wrap_s, s, texture.config.width);
t = texture.config.height - 1 - GetWrappedTexCoord(texture.config.wrap_t, t, texture.config.height);
u8* texture_data = Memory::GetPhysicalPointer(texture.config.GetPhysicalAddress());
auto info = DebugUtils::TextureInfo::FromPicaRegister(texture.config, texture.format);
texture_color[i] = DebugUtils::LookupTexture(texture_data, s, t, info);
DebugUtils::DumpTexture(texture.config, texture_data);
}
// Texture environment - consists of 6 stages of color and alpha combining.
//
// Color combiners take three input color values from some source (e.g. interpolated
// vertex color, texture color, previous stage, etc), perform some very simple
// operations on each of them (e.g. inversion) and then calculate the output color
// with some basic arithmetic. Alpha combiners can be configured separately but work
// analogously.
Math::Vec4<u8> combiner_output;
Math::Vec4<u8> combiner_buffer = {
regs.tev_combiner_buffer_color.r, regs.tev_combiner_buffer_color.g,
regs.tev_combiner_buffer_color.b, regs.tev_combiner_buffer_color.a
};
for (unsigned tev_stage_index = 0; tev_stage_index < tev_stages.size(); ++tev_stage_index) {
const auto& tev_stage = tev_stages[tev_stage_index];
using Source = Regs::TevStageConfig::Source;
using ColorModifier = Regs::TevStageConfig::ColorModifier;
using AlphaModifier = Regs::TevStageConfig::AlphaModifier;
using Operation = Regs::TevStageConfig::Operation;
auto GetSource = [&](Source source) -> Math::Vec4<u8> {
switch (source) {
// TODO: What's the difference between these two?
case Source::PrimaryColor:
case Source::PrimaryFragmentColor:
return primary_color;
case Source::Texture0:
return texture_color[0];
case Source::Texture1:
return texture_color[1];
case Source::Texture2:
return texture_color[2];
case Source::PreviousBuffer:
return combiner_buffer;
case Source::Constant:
return {tev_stage.const_r, tev_stage.const_g, tev_stage.const_b, tev_stage.const_a};
case Source::Previous:
return combiner_output;
default:
LOG_ERROR(HW_GPU, "Unknown color combiner source %d\n", (int)source);
UNIMPLEMENTED();
return {0, 0, 0, 0};
}
};
static auto GetColorModifier = [](ColorModifier factor, const Math::Vec4<u8>& values) -> Math::Vec3<u8> {
switch (factor) {
case ColorModifier::SourceColor:
return values.rgb();
case ColorModifier::OneMinusSourceColor:
return (Math::Vec3<u8>(255, 255, 255) - values.rgb()).Cast<u8>();
case ColorModifier::SourceAlpha:
return values.aaa();
case ColorModifier::OneMinusSourceAlpha:
return (Math::Vec3<u8>(255, 255, 255) - values.aaa()).Cast<u8>();
case ColorModifier::SourceRed:
return values.rrr();
case ColorModifier::OneMinusSourceRed:
return (Math::Vec3<u8>(255, 255, 255) - values.rrr()).Cast<u8>();
case ColorModifier::SourceGreen:
return values.ggg();
case ColorModifier::OneMinusSourceGreen:
return (Math::Vec3<u8>(255, 255, 255) - values.ggg()).Cast<u8>();
case ColorModifier::SourceBlue:
return values.bbb();
case ColorModifier::OneMinusSourceBlue:
return (Math::Vec3<u8>(255, 255, 255) - values.bbb()).Cast<u8>();
}
};
static auto GetAlphaModifier = [](AlphaModifier factor, const Math::Vec4<u8>& values) -> u8 {
switch (factor) {
case AlphaModifier::SourceAlpha:
return values.a();
case AlphaModifier::OneMinusSourceAlpha:
return 255 - values.a();
case AlphaModifier::SourceRed:
return values.r();
case AlphaModifier::OneMinusSourceRed:
return 255 - values.r();
case AlphaModifier::SourceGreen:
return values.g();
case AlphaModifier::OneMinusSourceGreen:
return 255 - values.g();
case AlphaModifier::SourceBlue:
return values.b();
case AlphaModifier::OneMinusSourceBlue:
return 255 - values.b();
}
};
static auto ColorCombine = [](Operation op, const Math::Vec3<u8> input[3]) -> Math::Vec3<u8> {
switch (op) {
case Operation::Replace:
return input[0];
case Operation::Modulate:
return ((input[0] * input[1]) / 255).Cast<u8>();
case Operation::Add:
{
auto result = input[0] + input[1];
result.r() = std::min(255, result.r());
result.g() = std::min(255, result.g());
result.b() = std::min(255, result.b());
return result.Cast<u8>();
}
case Operation::AddSigned:
{
// TODO(bunnei): Verify that the color conversion from (float) 0.5f to (byte) 128 is correct
auto result = input[0].Cast<int>() + input[1].Cast<int>() - Math::MakeVec<int>(128, 128, 128);
result.r() = MathUtil::Clamp<int>(result.r(), 0, 255);
result.g() = MathUtil::Clamp<int>(result.g(), 0, 255);
result.b() = MathUtil::Clamp<int>(result.b(), 0, 255);
return result.Cast<u8>();
}
case Operation::Lerp:
return ((input[0] * input[2] + input[1] * (Math::MakeVec<u8>(255, 255, 255) - input[2]).Cast<u8>()) / 255).Cast<u8>();
case Operation::Subtract:
{
auto result = input[0].Cast<int>() - input[1].Cast<int>();
result.r() = std::max(0, result.r());
result.g() = std::max(0, result.g());
result.b() = std::max(0, result.b());
return result.Cast<u8>();
}
case Operation::MultiplyThenAdd:
{
auto result = (input[0] * input[1] + 255 * input[2].Cast<int>()) / 255;
result.r() = std::min(255, result.r());
result.g() = std::min(255, result.g());
result.b() = std::min(255, result.b());
return result.Cast<u8>();
}
case Operation::AddThenMultiply:
{
auto result = input[0] + input[1];
result.r() = std::min(255, result.r());
result.g() = std::min(255, result.g());
result.b() = std::min(255, result.b());
result = (result * input[2].Cast<int>()) / 255;
return result.Cast<u8>();
}
default:
LOG_ERROR(HW_GPU, "Unknown color combiner operation %d\n", (int)op);
UNIMPLEMENTED();
return {0, 0, 0};
}
};
static auto AlphaCombine = [](Operation op, const std::array<u8,3>& input) -> u8 {
switch (op) {
case Operation::Replace:
return input[0];
case Operation::Modulate:
return input[0] * input[1] / 255;
case Operation::Add:
return std::min(255, input[0] + input[1]);
case Operation::Lerp:
return (input[0] * input[2] + input[1] * (255 - input[2])) / 255;
case Operation::Subtract:
return std::max(0, (int)input[0] - (int)input[1]);
case Operation::MultiplyThenAdd:
return std::min(255, (input[0] * input[1] + 255 * input[2]) / 255);
case Operation::AddThenMultiply:
return (std::min(255, (input[0] + input[1])) * input[2]) / 255;
default:
LOG_ERROR(HW_GPU, "Unknown alpha combiner operation %d\n", (int)op);
UNIMPLEMENTED();
return 0;
}
};
// color combiner
// NOTE: Not sure if the alpha combiner might use the color output of the previous
// stage as input. Hence, we currently don't directly write the result to
// combiner_output.rgb(), but instead store it in a temporary variable until
// alpha combining has been done.
Math::Vec3<u8> color_result[3] = {
GetColorModifier(tev_stage.color_modifier1, GetSource(tev_stage.color_source1)),
GetColorModifier(tev_stage.color_modifier2, GetSource(tev_stage.color_source2)),
GetColorModifier(tev_stage.color_modifier3, GetSource(tev_stage.color_source3))
};
auto color_output = ColorCombine(tev_stage.color_op, color_result);
// alpha combiner
std::array<u8,3> alpha_result = {
GetAlphaModifier(tev_stage.alpha_modifier1, GetSource(tev_stage.alpha_source1)),
GetAlphaModifier(tev_stage.alpha_modifier2, GetSource(tev_stage.alpha_source2)),
GetAlphaModifier(tev_stage.alpha_modifier3, GetSource(tev_stage.alpha_source3))
};
auto alpha_output = AlphaCombine(tev_stage.alpha_op, alpha_result);
combiner_output[0] = std::min((unsigned)255, color_output.r() * tev_stage.GetColorMultiplier());
combiner_output[1] = std::min((unsigned)255, color_output.g() * tev_stage.GetColorMultiplier());
combiner_output[2] = std::min((unsigned)255, color_output.b() * tev_stage.GetColorMultiplier());
combiner_output[3] = std::min((unsigned)255, alpha_output * tev_stage.GetAlphaMultiplier());
if (regs.tev_combiner_buffer_input.TevStageUpdatesCombinerBufferColor(tev_stage_index)) {
combiner_buffer.r() = combiner_output.r();
combiner_buffer.g() = combiner_output.g();
combiner_buffer.b() = combiner_output.b();
}
if (regs.tev_combiner_buffer_input.TevStageUpdatesCombinerBufferAlpha(tev_stage_index)) {
combiner_buffer.a() = combiner_output.a();
}
}
const auto& output_merger = regs.output_merger;
if (output_merger.alpha_test.enable) {
bool pass = false;
switch (output_merger.alpha_test.func) {
case Regs::CompareFunc::Never:
pass = false;
break;
case Regs::CompareFunc::Always:
pass = true;
break;
case Regs::CompareFunc::Equal:
pass = combiner_output.a() == output_merger.alpha_test.ref;
break;
case Regs::CompareFunc::NotEqual:
pass = combiner_output.a() != output_merger.alpha_test.ref;
break;
case Regs::CompareFunc::LessThan:
pass = combiner_output.a() < output_merger.alpha_test.ref;
break;
case Regs::CompareFunc::LessThanOrEqual:
pass = combiner_output.a() <= output_merger.alpha_test.ref;
break;
case Regs::CompareFunc::GreaterThan:
pass = combiner_output.a() > output_merger.alpha_test.ref;
break;
case Regs::CompareFunc::GreaterThanOrEqual:
pass = combiner_output.a() >= output_merger.alpha_test.ref;
break;
}
if (!pass)
continue;
}
// TODO: Does depth indeed only get written even if depth testing is enabled?
if (output_merger.depth_test_enable) {
unsigned num_bits = Regs::DepthBitsPerPixel(regs.framebuffer.depth_format);
u32 z = (u32)((v0.screenpos[2].ToFloat32() * w0 +
v1.screenpos[2].ToFloat32() * w1 +
v2.screenpos[2].ToFloat32() * w2) * ((1 << num_bits) - 1) / wsum);
u32 ref_z = GetDepth(x >> 4, y >> 4);
bool pass = false;
switch (output_merger.depth_test_func) {
case Regs::CompareFunc::Never:
pass = false;
break;
case Regs::CompareFunc::Always:
pass = true;
break;
case Regs::CompareFunc::Equal:
pass = z == ref_z;
break;
case Regs::CompareFunc::NotEqual:
pass = z != ref_z;
break;
case Regs::CompareFunc::LessThan:
pass = z < ref_z;
break;
case Regs::CompareFunc::LessThanOrEqual:
pass = z <= ref_z;
break;
case Regs::CompareFunc::GreaterThan:
pass = z > ref_z;
break;
case Regs::CompareFunc::GreaterThanOrEqual:
pass = z >= ref_z;
break;
}
if (!pass)
continue;
if (output_merger.depth_write_enable)
SetDepth(x >> 4, y >> 4, z);
}
auto dest = GetPixel(x >> 4, y >> 4);
Math::Vec4<u8> blend_output = combiner_output;
if (output_merger.alphablend_enable) {
auto params = output_merger.alpha_blending;
auto LookupFactorRGB = [&](Regs::BlendFactor factor) -> Math::Vec3<u8> {
switch (factor) {
case Regs::BlendFactor::Zero :
return Math::Vec3<u8>(0, 0, 0);
case Regs::BlendFactor::One :
return Math::Vec3<u8>(255, 255, 255);
case Regs::BlendFactor::SourceColor:
return combiner_output.rgb();
case Regs::BlendFactor::OneMinusSourceColor:
return Math::Vec3<u8>(255 - combiner_output.r(), 255 - combiner_output.g(), 255 - combiner_output.b());
case Regs::BlendFactor::DestColor:
return dest.rgb();
case Regs::BlendFactor::OneMinusDestColor:
return Math::Vec3<u8>(255 - dest.r(), 255 - dest.g(), 255 - dest.b());
case Regs::BlendFactor::SourceAlpha:
return Math::Vec3<u8>(combiner_output.a(), combiner_output.a(), combiner_output.a());
case Regs::BlendFactor::OneMinusSourceAlpha:
return Math::Vec3<u8>(255 - combiner_output.a(), 255 - combiner_output.a(), 255 - combiner_output.a());
case Regs::BlendFactor::DestAlpha:
return Math::Vec3<u8>(dest.a(), dest.a(), dest.a());
case Regs::BlendFactor::OneMinusDestAlpha:
return Math::Vec3<u8>(255 - dest.a(), 255 - dest.a(), 255 - dest.a());
case Regs::BlendFactor::ConstantColor:
return Math::Vec3<u8>(output_merger.blend_const.r, output_merger.blend_const.g, output_merger.blend_const.b);
case Regs::BlendFactor::OneMinusConstantColor:
return Math::Vec3<u8>(255 - output_merger.blend_const.r, 255 - output_merger.blend_const.g, 255 - output_merger.blend_const.b);
case Regs::BlendFactor::ConstantAlpha:
return Math::Vec3<u8>(output_merger.blend_const.a, output_merger.blend_const.a, output_merger.blend_const.a);
case Regs::BlendFactor::OneMinusConstantAlpha:
return Math::Vec3<u8>(255 - output_merger.blend_const.a, 255 - output_merger.blend_const.a, 255 - output_merger.blend_const.a);
default:
LOG_CRITICAL(HW_GPU, "Unknown color blend factor %x", factor);
UNIMPLEMENTED();
break;
}
};
auto LookupFactorA = [&](Regs::BlendFactor factor) -> u8 {
switch (factor) {
case Regs::BlendFactor::Zero:
return 0;
case Regs::BlendFactor::One:
return 255;
case Regs::BlendFactor::SourceAlpha:
return combiner_output.a();
case Regs::BlendFactor::OneMinusSourceAlpha:
return 255 - combiner_output.a();
case Regs::BlendFactor::DestAlpha:
return dest.a();
case Regs::BlendFactor::OneMinusDestAlpha:
return 255 - dest.a();
case Regs::BlendFactor::ConstantAlpha:
return output_merger.blend_const.a;
case Regs::BlendFactor::OneMinusConstantAlpha:
return 255 - output_merger.blend_const.a;
default:
LOG_CRITICAL(HW_GPU, "Unknown alpha blend factor %x", factor);
UNIMPLEMENTED();
break;
}
};
using BlendEquation = Regs::BlendEquation;
static auto EvaluateBlendEquation = [](const Math::Vec4<u8>& src, const Math::Vec4<u8>& srcfactor,
const Math::Vec4<u8>& dest, const Math::Vec4<u8>& destfactor,
BlendEquation equation) {
Math::Vec4<int> result;
auto src_result = (src * srcfactor).Cast<int>();
auto dst_result = (dest * destfactor).Cast<int>();
switch (equation) {
case Regs::BlendEquation::Add:
result = (src_result + dst_result) / 255;
break;
case Regs::BlendEquation::Subtract:
result = (src_result - dst_result) / 255;
break;
case Regs::BlendEquation::ReverseSubtract:
result = (dst_result - src_result) / 255;
break;
// TODO: How do these two actually work?
// OpenGL doesn't include the blend factors in the min/max computations,
// but is this what the 3DS actually does?
case Regs::BlendEquation::Min:
result.r() = std::min(src.r(), dest.r());
result.g() = std::min(src.g(), dest.g());
result.b() = std::min(src.b(), dest.b());
result.a() = std::min(src.a(), dest.a());
break;
case Regs::BlendEquation::Max:
result.r() = std::max(src.r(), dest.r());
result.g() = std::max(src.g(), dest.g());
result.b() = std::max(src.b(), dest.b());
result.a() = std::max(src.a(), dest.a());
break;
default:
LOG_CRITICAL(HW_GPU, "Unknown RGB blend equation %x", equation);
UNIMPLEMENTED();
}
return Math::Vec4<u8>(MathUtil::Clamp(result.r(), 0, 255),
MathUtil::Clamp(result.g(), 0, 255),
MathUtil::Clamp(result.b(), 0, 255),
MathUtil::Clamp(result.a(), 0, 255));
};
auto srcfactor = Math::MakeVec(LookupFactorRGB(params.factor_source_rgb),
LookupFactorA(params.factor_source_a));
auto dstfactor = Math::MakeVec(LookupFactorRGB(params.factor_dest_rgb),
LookupFactorA(params.factor_dest_a));
blend_output = EvaluateBlendEquation(combiner_output, srcfactor, dest, dstfactor, params.blend_equation_rgb);
blend_output.a() = EvaluateBlendEquation(combiner_output, srcfactor, dest, dstfactor, params.blend_equation_a).a();
} else {
LOG_CRITICAL(HW_GPU, "logic op: %x", output_merger.logic_op);
UNIMPLEMENTED();
}
const Math::Vec4<u8> result = {
output_merger.red_enable ? blend_output.r() : dest.r(),
output_merger.green_enable ? blend_output.g() : dest.g(),
output_merger.blue_enable ? blend_output.b() : dest.b(),
output_merger.alpha_enable ? blend_output.a() : dest.a()
};
DrawPixel(x >> 4, y >> 4, result);
}
}
}
void ProcessTriangle(const VertexShader::OutputVertex& v0,
const VertexShader::OutputVertex& v1,
const VertexShader::OutputVertex& v2) {
ProcessTriangleInternal(v0, v1, v2);
}
} // namespace Rasterizer
} // namespace Pica
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