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GPU/HW: Work around rasterization differences in OpenGL

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Strangely, AMD GPUs are fine, it's just NVIDIA and Intel. Time for a
Vulkan renderer?
This commit is contained in:
Connor McLaughlin 2020-04-29 21:17:47 +10:00
parent 940b725c1d
commit 557a6c3696
1 changed files with 6 additions and 9 deletions
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15
src/core/gpu_hw_shadergen.cpp
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@ -388,6 +388,8 @@ std::string GPU_HW_ShaderGen::GenerateBatchVertexShader(bool textured)
WriteCommonFunctions(ss);
WriteBatchUniformBuffer(ss);
ss << "CONSTANT float EPSILON = 0.00001;\n";
if (textured)
{
DeclareVertexEntryPoint(ss, {"int2 a_pos", "float4 a_col0", "uint a_texcoord", "uint a_texpage"}, 1, 1,
@ -409,9 +411,10 @@ std::string GPU_HW_ShaderGen::GenerateBatchVertexShader(bool textured)
float pos_x = ((float(a_pos.x) + vertex_offset) / 512.0) - 1.0;
float pos_y = ((float(a_pos.y) + vertex_offset) / -256.0) + 1.0;
// OpenGL seems to be off by one pixel in the Y direction due to lower-left origin.
// OpenGL seems to be off by one pixel in the Y direction due to lower-left origin, but only on
// Intel and NVIDIA drivers. AMD is fine...
#if API_OPENGL || API_OPENGL_ES
pos_y += (1.0 / 512.0);
pos_y += EPSILON;
#endif
v_pos = float4(pos_x, pos_y, 0.0, 1.0);
@ -419,13 +422,7 @@ std::string GPU_HW_ShaderGen::GenerateBatchVertexShader(bool textured)
#if TEXTURED
// Fudge the texture coordinates by half a pixel in screen-space.
// This fixes the rounding/interpolation error on NVIDIA GPUs with shared edges between triangles.
#if API_OPENGL || API_OPENGL_ES
v_tex0 = float2(float(a_texcoord & 0xFFFFu) + (RCP_VRAM_SIZE.x * 0.5),
float(a_texcoord >> 16) - (RCP_VRAM_SIZE.y * 0.5));
#else
v_tex0 = float2(float(a_texcoord & 0xFFFFu) + (RCP_VRAM_SIZE.x * 0.5),
float(a_texcoord >> 16) + (RCP_VRAM_SIZE.y * 0.5));
#endif
v_tex0 = float2(float(a_texcoord & 0xFFFFu) + EPSILON, float(a_texcoord >> 16) + EPSILON);
// base_x,base_y,palette_x,palette_y
v_texpage.x = (a_texpage & 15u) * 64u * RESOLUTION_SCALE;