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Merge pull request #11269 from unknownbrackets/fragtest
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Avoid discard when we can blend
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@hrydgard
hrydgard committed Jul 29, 2018
2 parents ec650ad + 5ccd3ee commit a776dce
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Showing 6 changed files with 56 additions and 29 deletions.
18 changes: 18 additions & 0 deletions GPU/Common/GPUStateUtils.cpp
View file
Expand Up @@ -113,6 +113,24 @@ bool IsAlphaTestTriviallyTrue() {
} }
} }


bool NeedsTestDiscard() {
// We assume this is called only when enabled and not trivially true (may also be for color testing.)
if (gstate.isStencilTestEnabled() && (gstate.pmska & 0xFF) != 0xFF)
return true;
if (gstate.isDepthTestEnabled() && gstate.isDepthWriteEnabled())
return true;
if (!gstate.isAlphaBlendEnabled())
return true;
if (gstate.isLogicOpEnabled() && gstate.getLogicOp() != GE_LOGIC_COPY)
return true;
if (gstate.getBlendFuncA() != GE_SRCBLEND_SRCALPHA && gstate.getBlendFuncA() != GE_DSTBLEND_DOUBLESRCALPHA)
return true;
if (!safeDestFactors[(int)gstate.getBlendFuncB()])
return true;

return false;
}

bool IsAlphaTestAgainstZero() { bool IsAlphaTestAgainstZero() {
return gstate.getAlphaTestRef() == 0 && gstate.getAlphaTestMask() == 0xFF; return gstate.getAlphaTestRef() == 0 && gstate.getAlphaTestMask() == 0xFF;
} }
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1 change: 1 addition & 0 deletions GPU/Common/GPUStateUtils.h
View file
Expand Up @@ -44,6 +44,7 @@ bool IsAlphaTestTriviallyTrue();
bool IsColorTestAgainstZero(); bool IsColorTestAgainstZero();
bool IsColorTestTriviallyTrue(); bool IsColorTestTriviallyTrue();
bool IsAlphaTestAgainstZero(); bool IsAlphaTestAgainstZero();
bool NeedsTestDiscard();


StencilValueType ReplaceAlphaWithStencilType(); StencilValueType ReplaceAlphaWithStencilType();
ReplaceAlphaType ReplaceAlphaWithStencil(ReplaceBlendType replaceBlend); ReplaceAlphaType ReplaceAlphaWithStencil(ReplaceBlendType replaceBlend);
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3 changes: 3 additions & 0 deletions GPU/Common/ShaderId.cpp
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Expand Up @@ -268,12 +268,15 @@ void ComputeFragmentShaderID(ShaderID *id_out) {
id.SetBit(FS_BIT_ALPHA_TEST); id.SetBit(FS_BIT_ALPHA_TEST);
id.SetBits(FS_BIT_ALPHA_TEST_FUNC, 3, gstate.getAlphaTestFunction()); id.SetBits(FS_BIT_ALPHA_TEST_FUNC, 3, gstate.getAlphaTestFunction());
id.SetBit(FS_BIT_ALPHA_AGAINST_ZERO, IsAlphaTestAgainstZero()); id.SetBit(FS_BIT_ALPHA_AGAINST_ZERO, IsAlphaTestAgainstZero());
id.SetBit(FS_BIT_TEST_DISCARD_TO_ZERO, !NeedsTestDiscard());
} }
if (enableColorTest) { if (enableColorTest) {
// 4 bits total. // 4 bits total.
id.SetBit(FS_BIT_COLOR_TEST); id.SetBit(FS_BIT_COLOR_TEST);
id.SetBits(FS_BIT_COLOR_TEST_FUNC, 2, gstate.getColorTestFunction()); id.SetBits(FS_BIT_COLOR_TEST_FUNC, 2, gstate.getColorTestFunction());
id.SetBit(FS_BIT_COLOR_AGAINST_ZERO, IsColorTestAgainstZero()); id.SetBit(FS_BIT_COLOR_AGAINST_ZERO, IsColorTestAgainstZero());
// This is alos set in enableAlphaTest - color test is uncommon, but we can skip discard the same way.
id.SetBit(FS_BIT_TEST_DISCARD_TO_ZERO, !NeedsTestDiscard());
} }


id.SetBit(FS_BIT_ENABLE_FOG, enableFog); id.SetBit(FS_BIT_ENABLE_FOG, enableFog);
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3 changes: 2 additions & 1 deletion GPU/Common/ShaderId.h
View file
Expand Up @@ -86,7 +86,8 @@ enum {
FS_BIT_BLENDFUNC_B = 42, // 4 bits FS_BIT_BLENDFUNC_B = 42, // 4 bits
FS_BIT_FLATSHADE = 46, FS_BIT_FLATSHADE = 46,
FS_BIT_BGRA_TEXTURE = 47, FS_BIT_BGRA_TEXTURE = 47,
// 48+ are free. FS_BIT_TEST_DISCARD_TO_ZERO = 48,
// 49+ are free.
}; };


struct ShaderID { struct ShaderID {
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36 changes: 19 additions & 17 deletions GPU/GLES/FragmentShaderGeneratorGLES.cpp
View file
Expand Up @@ -151,6 +151,7 @@ bool GenerateFragmentShader(const FShaderID &id, char *buffer, uint64_t *uniform
bool enableAlphaTest = id.Bit(FS_BIT_ALPHA_TEST); bool enableAlphaTest = id.Bit(FS_BIT_ALPHA_TEST);


bool alphaTestAgainstZero = id.Bit(FS_BIT_ALPHA_AGAINST_ZERO); bool alphaTestAgainstZero = id.Bit(FS_BIT_ALPHA_AGAINST_ZERO);
bool testForceToZero = id.Bit(FS_BIT_TEST_DISCARD_TO_ZERO);
bool enableColorTest = id.Bit(FS_BIT_COLOR_TEST); bool enableColorTest = id.Bit(FS_BIT_COLOR_TEST);
bool colorTestAgainstZero = id.Bit(FS_BIT_COLOR_AGAINST_ZERO); bool colorTestAgainstZero = id.Bit(FS_BIT_COLOR_AGAINST_ZERO);
bool enableColorDoubling = id.Bit(FS_BIT_COLOR_DOUBLE); bool enableColorDoubling = id.Bit(FS_BIT_COLOR_DOUBLE);
Expand Down Expand Up @@ -510,39 +511,40 @@ bool GenerateFragmentShader(const FShaderID &id, char *buffer, uint64_t *uniform
} }
} }


const char *discardStatement = testForceToZero ? "v.a = 0.0;" : "discard;";
if (enableAlphaTest) { if (enableAlphaTest) {
if (alphaTestAgainstZero) { if (alphaTestAgainstZero) {
// When testing against 0 (extremely common), we can avoid some math. // When testing against 0 (extremely common), we can avoid some math.
// 0.002 is approximately half of 1.0 / 255.0. // 0.002 is approximately half of 1.0 / 255.0.
if (alphaTestFunc == GE_COMP_NOTEQUAL || alphaTestFunc == GE_COMP_GREATER) { if (alphaTestFunc == GE_COMP_NOTEQUAL || alphaTestFunc == GE_COMP_GREATER) {
WRITE(p, " if (v.a < 0.002) discard;\n"); WRITE(p, " if (v.a < 0.002) %s\n", discardStatement);
} else if (alphaTestFunc != GE_COMP_NEVER) { } else if (alphaTestFunc != GE_COMP_NEVER) {
// Anything else is a test for == 0. Happens sometimes, actually... // Anything else is a test for == 0. Happens sometimes, actually...
WRITE(p, " if (v.a > 0.002) discard;\n"); WRITE(p, " if (v.a > 0.002) %s\n", discardStatement);
} else { } else {
// NEVER has been logged as used by games, although it makes little sense - statically failing. // NEVER has been logged as used by games, although it makes little sense - statically failing.
// Maybe we could discard the drawcall, but it's pretty rare. Let's just statically discard here. // Maybe we could discard the drawcall, but it's pretty rare. Let's just statically discard here.
WRITE(p, " discard;\n"); WRITE(p, " %s\n", discardStatement);
} }
} else if (g_Config.bFragmentTestCache) { } else if (g_Config.bFragmentTestCache) {
WRITE(p, " float aResult = %s(testtex, vec2(%s, 0)).a;\n", texture, alphaTestXCoord.c_str()); WRITE(p, " float aResult = %s(testtex, vec2(%s, 0)).a;\n", texture, alphaTestXCoord.c_str());
WRITE(p, " if (aResult < 0.5) discard;\n"); WRITE(p, " if (aResult < 0.5) %s\n", discardStatement);
} else { } else {
const char *alphaTestFuncs[] = { "#", "#", " != ", " == ", " >= ", " > ", " <= ", " < " }; const char *alphaTestFuncs[] = { "#", "#", " != ", " == ", " >= ", " > ", " <= ", " < " };
if (alphaTestFuncs[alphaTestFunc][0] != '#') { if (alphaTestFuncs[alphaTestFunc][0] != '#') {
if (bitwiseOps) { if (bitwiseOps) {
WRITE(p, " if ((roundAndScaleTo255i(v.a) & u_alphacolormask.a) %s int(u_alphacolorref.a)) discard;\n", alphaTestFuncs[alphaTestFunc]); WRITE(p, " if ((roundAndScaleTo255i(v.a) & u_alphacolormask.a) %s int(u_alphacolorref.a)) %s\n", alphaTestFuncs[alphaTestFunc], discardStatement);
} else if (gl_extensions.gpuVendor == GPU_VENDOR_IMGTEC) { } else if (gl_extensions.gpuVendor == GPU_VENDOR_IMGTEC) {
// Work around bad PVR driver problem where equality check + discard just doesn't work. // Work around bad PVR driver problem where equality check + discard just doesn't work.
if (alphaTestFunc != GE_COMP_NOTEQUAL) { if (alphaTestFunc != GE_COMP_NOTEQUAL) {
WRITE(p, " if (roundTo255thf(v.a) %s u_alphacolorref.a) discard;\n", alphaTestFuncs[alphaTestFunc]); WRITE(p, " if (roundTo255thf(v.a) %s u_alphacolorref.a) %s\n", alphaTestFuncs[alphaTestFunc], discardStatement);
} }
} else { } else {
WRITE(p, " if (roundAndScaleTo255f(v.a) %s u_alphacolorref.a) discard;\n", alphaTestFuncs[alphaTestFunc]); WRITE(p, " if (roundAndScaleTo255f(v.a) %s u_alphacolorref.a) %s\n", alphaTestFuncs[alphaTestFunc], discardStatement);
} }
} else { } else {
// This means NEVER. See above. // This means NEVER. See above.
WRITE(p, " discard;\n"); WRITE(p, " %s\n", discardStatement);
} }
} }
} }
Expand All @@ -552,25 +554,25 @@ bool GenerateFragmentShader(const FShaderID &id, char *buffer, uint64_t *uniform
// When testing against 0 (common), we can avoid some math. // When testing against 0 (common), we can avoid some math.
// 0.002 is approximately half of 1.0 / 255.0. // 0.002 is approximately half of 1.0 / 255.0.
if (colorTestFunc == GE_COMP_NOTEQUAL) { if (colorTestFunc == GE_COMP_NOTEQUAL) {
WRITE(p, " if (v.r < 0.002 && v.g < 0.002 && v.b < 0.002) discard;\n"); WRITE(p, " if (v.r < 0.002 && v.g < 0.002 && v.b < 0.002) %s\n", discardStatement);
} else if (colorTestFunc != GE_COMP_NEVER) { } else if (colorTestFunc != GE_COMP_NEVER) {
// Anything else is a test for == 0. // Anything else is a test for == 0.
WRITE(p, " if (v.r > 0.002 || v.g > 0.002 || v.b > 0.002) discard;\n"); WRITE(p, " if (v.r > 0.002 || v.g > 0.002 || v.b > 0.002) %s\n", discardStatement);
} else { } else {
// NEVER has been logged as used by games, although it makes little sense - statically failing. // NEVER has been logged as used by games, although it makes little sense - statically failing.
// Maybe we could discard the drawcall, but it's pretty rare. Let's just statically discard here. // Maybe we could discard the drawcall, but it's pretty rare. Let's just statically discard here.
WRITE(p, " discard;\n"); WRITE(p, " %s\n", discardStatement);
} }
} else if (g_Config.bFragmentTestCache) { } else if (g_Config.bFragmentTestCache) {
WRITE(p, " float rResult = %s(testtex, vec2(vScale256.r, 0)).r;\n", texture); WRITE(p, " float rResult = %s(testtex, vec2(vScale256.r, 0)).r;\n", texture);
WRITE(p, " float gResult = %s(testtex, vec2(vScale256.g, 0)).g;\n", texture); WRITE(p, " float gResult = %s(testtex, vec2(vScale256.g, 0)).g;\n", texture);
WRITE(p, " float bResult = %s(testtex, vec2(vScale256.b, 0)).b;\n", texture); WRITE(p, " float bResult = %s(testtex, vec2(vScale256.b, 0)).b;\n", texture);
if (colorTestFunc == GE_COMP_EQUAL) { if (colorTestFunc == GE_COMP_EQUAL) {
// Equal means all parts must be equal. // Equal means all parts must be equal.
WRITE(p, " if (rResult < 0.5 || gResult < 0.5 || bResult < 0.5) discard;\n"); WRITE(p, " if (rResult < 0.5 || gResult < 0.5 || bResult < 0.5) %s\n", discardStatement);
} else { } else {
// Not equal means any part must be not equal. // Not equal means any part must be not equal.
WRITE(p, " if (rResult < 0.5 && gResult < 0.5 && bResult < 0.5) discard;\n"); WRITE(p, " if (rResult < 0.5 && gResult < 0.5 && bResult < 0.5) %s\n", discardStatement);
} }
} else { } else {
const char *colorTestFuncs[] = { "#", "#", " != ", " == " }; const char *colorTestFuncs[] = { "#", "#", " != ", " == " };
Expand All @@ -580,14 +582,14 @@ bool GenerateFragmentShader(const FShaderID &id, char *buffer, uint64_t *uniform
WRITE(p, " ivec3 v_scaled = roundAndScaleTo255iv(v.rgb);\n"); WRITE(p, " ivec3 v_scaled = roundAndScaleTo255iv(v.rgb);\n");
const char *maskedFragColor = "ivec3(v_scaled.r & u_alphacolormask.r, v_scaled.g & u_alphacolormask.g, v_scaled.b & u_alphacolormask.b)"; const char *maskedFragColor = "ivec3(v_scaled.r & u_alphacolormask.r, v_scaled.g & u_alphacolormask.g, v_scaled.b & u_alphacolormask.b)";
const char *maskedColorRef = "ivec3(int(u_alphacolorref.r) & u_alphacolormask.r, int(u_alphacolorref.g) & u_alphacolormask.g, int(u_alphacolorref.b) & u_alphacolormask.b)"; const char *maskedColorRef = "ivec3(int(u_alphacolorref.r) & u_alphacolormask.r, int(u_alphacolorref.g) & u_alphacolormask.g, int(u_alphacolorref.b) & u_alphacolormask.b)";
WRITE(p, " if (%s %s %s) discard;\n", maskedFragColor, colorTestFuncs[colorTestFunc], maskedColorRef); WRITE(p, " if (%s %s %s) %s\n", maskedFragColor, colorTestFuncs[colorTestFunc], maskedColorRef, discardStatement);
} else if (gl_extensions.gpuVendor == GPU_VENDOR_IMGTEC) { } else if (gl_extensions.gpuVendor == GPU_VENDOR_IMGTEC) {
WRITE(p, " if (roundTo255thv(v.rgb) %s u_alphacolorref.rgb) discard;\n", colorTestFuncs[colorTestFunc]); WRITE(p, " if (roundTo255thv(v.rgb) %s u_alphacolorref.rgb) %s\n", colorTestFuncs[colorTestFunc], discardStatement);
} else { } else {
WRITE(p, " if (roundAndScaleTo255v(v.rgb) %s u_alphacolorref.rgb) discard;\n", colorTestFuncs[colorTestFunc]); WRITE(p, " if (roundAndScaleTo255v(v.rgb) %s u_alphacolorref.rgb) %s\n", colorTestFuncs[colorTestFunc], discardStatement);
} }
} else { } else {
WRITE(p, " discard;\n"); WRITE(p, " %s\n", discardStatement);
} }
} }
} }
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24 changes: 13 additions & 11 deletions GPU/Vulkan/FragmentShaderGeneratorVulkan.cpp
View file
Expand Up @@ -56,6 +56,7 @@ bool GenerateVulkanGLSLFragmentShader(const FShaderID &id, char *buffer) {
bool enableAlphaTest = id.Bit(FS_BIT_ALPHA_TEST); bool enableAlphaTest = id.Bit(FS_BIT_ALPHA_TEST);


bool alphaTestAgainstZero = id.Bit(FS_BIT_ALPHA_AGAINST_ZERO); bool alphaTestAgainstZero = id.Bit(FS_BIT_ALPHA_AGAINST_ZERO);
bool testForceToZero = id.Bit(FS_BIT_TEST_DISCARD_TO_ZERO);
bool enableColorTest = id.Bit(FS_BIT_COLOR_TEST); bool enableColorTest = id.Bit(FS_BIT_COLOR_TEST);
bool colorTestAgainstZero = id.Bit(FS_BIT_COLOR_AGAINST_ZERO); bool colorTestAgainstZero = id.Bit(FS_BIT_COLOR_AGAINST_ZERO);
bool enableColorDoubling = id.Bit(FS_BIT_COLOR_DOUBLE); bool enableColorDoubling = id.Bit(FS_BIT_COLOR_DOUBLE);
Expand All @@ -82,7 +83,7 @@ bool GenerateVulkanGLSLFragmentShader(const FShaderID &id, char *buffer) {
bool isModeClear = id.Bit(FS_BIT_CLEARMODE); bool isModeClear = id.Bit(FS_BIT_CLEARMODE);


const char *shading = doFlatShading ? "flat" : ""; const char *shading = doFlatShading ? "flat" : "";
bool earlyFragmentTests = !enableAlphaTest && !enableColorTest && !gstate_c.Supports(GPU_ROUND_FRAGMENT_DEPTH_TO_16BIT); bool earlyFragmentTests = ((!enableAlphaTest && !enableColorTest) || testForceToZero) && !gstate_c.Supports(GPU_ROUND_FRAGMENT_DEPTH_TO_16BIT);


if (earlyFragmentTests) { if (earlyFragmentTests) {
WRITE(p, "layout (early_fragment_tests) in;\n"); WRITE(p, "layout (early_fragment_tests) in;\n");
Expand Down Expand Up @@ -347,27 +348,28 @@ bool GenerateVulkanGLSLFragmentShader(const FShaderID &id, char *buffer) {
// So we have to scale to account for the difference. // So we have to scale to account for the difference.
std::string alphaTestXCoord = "0"; std::string alphaTestXCoord = "0";


const char *discardStatement = testForceToZero ? "v.a = 0.0;" : "discard;";
if (enableAlphaTest) { if (enableAlphaTest) {
if (alphaTestAgainstZero) { if (alphaTestAgainstZero) {
// When testing against 0 (extremely common), we can avoid some math. // When testing against 0 (extremely common), we can avoid some math.
// 0.002 is approximately half of 1.0 / 255.0. // 0.002 is approximately half of 1.0 / 255.0.
if (alphaTestFunc == GE_COMP_NOTEQUAL || alphaTestFunc == GE_COMP_GREATER) { if (alphaTestFunc == GE_COMP_NOTEQUAL || alphaTestFunc == GE_COMP_GREATER) {
WRITE(p, " if (v.a < 0.002) discard;\n"); WRITE(p, " if (v.a < 0.002) %s\n", discardStatement);
} else if (alphaTestFunc != GE_COMP_NEVER) { } else if (alphaTestFunc != GE_COMP_NEVER) {
// Anything else is a test for == 0. Happens sometimes, actually... // Anything else is a test for == 0. Happens sometimes, actually...
WRITE(p, " if (v.a > 0.002) discard;\n"); WRITE(p, " if (v.a > 0.002) %s\n", discardStatement);
} else { } else {
// NEVER has been logged as used by games, although it makes little sense - statically failing. // NEVER has been logged as used by games, although it makes little sense - statically failing.
// Maybe we could discard the drawcall, but it's pretty rare. Let's just statically discard here. // Maybe we could discard the drawcall, but it's pretty rare. Let's just statically discard here.
WRITE(p, " discard;\n"); WRITE(p, " %s\n", discardStatement);
} }
} else { } else {
const char *alphaTestFuncs[] = { "#", "#", " != ", " == ", " >= ", " > ", " <= ", " < " }; const char *alphaTestFuncs[] = { "#", "#", " != ", " == ", " >= ", " > ", " <= ", " < " };
if (alphaTestFuncs[alphaTestFunc][0] != '#') { if (alphaTestFuncs[alphaTestFunc][0] != '#') {
WRITE(p, " if ((roundAndScaleTo255i(v.a) & base.alphacolormask.a) %s base.alphacolorref.a) discard;\n", alphaTestFuncs[alphaTestFunc]); WRITE(p, " if ((roundAndScaleTo255i(v.a) & base.alphacolormask.a) %s base.alphacolorref.a) %s\n", alphaTestFuncs[alphaTestFunc], discardStatement);
} else { } else {
// This means NEVER. See above. // This means NEVER. See above.
WRITE(p, " discard;\n"); WRITE(p, " %s\n", discardStatement);
} }
} }
} }
Expand All @@ -378,22 +380,22 @@ bool GenerateVulkanGLSLFragmentShader(const FShaderID &id, char *buffer) {
// Have my doubts that this special case is actually worth it, but whatever. // Have my doubts that this special case is actually worth it, but whatever.
// 0.002 is approximately half of 1.0 / 255.0. // 0.002 is approximately half of 1.0 / 255.0.
if (colorTestFunc == GE_COMP_NOTEQUAL) { if (colorTestFunc == GE_COMP_NOTEQUAL) {
WRITE(p, " if (v.r + v.g + v.b < 0.002) discard;\n"); WRITE(p, " if (v.r + v.g + v.b < 0.002) %s\n", discardStatement);
} else if (colorTestFunc != GE_COMP_NEVER) { } else if (colorTestFunc != GE_COMP_NEVER) {
// Anything else is a test for == 0. // Anything else is a test for == 0.
WRITE(p, " if (v.r + v.g + v.b > 0.002) discard;\n"); WRITE(p, " if (v.r + v.g + v.b > 0.002) %s\n", discardStatement);
} else { } else {
// NEVER has been logged as used by games, although it makes little sense - statically failing. // NEVER has been logged as used by games, although it makes little sense - statically failing.
// Maybe we could discard the drawcall, but it's pretty rare. Let's just statically discard here. // Maybe we could discard the drawcall, but it's pretty rare. Let's just statically discard here.
WRITE(p, " discard;\n"); WRITE(p, " %s\n", discardStatement);
} }
} else { } else {
const char *colorTestFuncs[] = { "#", "#", " != ", " == " }; const char *colorTestFuncs[] = { "#", "#", " != ", " == " };
if (colorTestFuncs[colorTestFunc][0] != '#') { if (colorTestFuncs[colorTestFunc][0] != '#') {
WRITE(p, " ivec3 v_scaled = roundAndScaleTo255iv(v.rgb);\n"); WRITE(p, " ivec3 v_scaled = roundAndScaleTo255iv(v.rgb);\n");
WRITE(p, " if ((v_scaled & base.alphacolormask.rgb) %s (base.alphacolorref.rgb & base.alphacolormask.rgb)) discard;\n", colorTestFuncs[colorTestFunc]); WRITE(p, " if ((v_scaled & base.alphacolormask.rgb) %s (base.alphacolorref.rgb & base.alphacolormask.rgb)) %s\n", colorTestFuncs[colorTestFunc], discardStatement);
} else { } else {
WRITE(p, " discard;\n"); WRITE(p, " %s\n", discardStatement);
} }
} }
} }
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