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GL renderer: Add fallback for when driver doesn't provide glDrawRangeElementsBaseVertex (#617)

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* GL: Add fallback for when driver doesn't provide glDrawRangeElementsBaseVertex

* GL: Fix fallback when glDrawRangeElementsBaseVertex is absent
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wheremyfoodat 2024-10-23 22:43:58 +03:00 • committed by GitHub
parent 54d0618f02
commit cdc61ea95a
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GPG key ID: B5690EEEBB952194
2 changed files with 45 additions and 6 deletions
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21
include/PICA/pica_simd.hpp
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@ -250,4 +250,25 @@ namespace PICA::IndexBuffer {
return analyzePortable<useShortIndices>(indexBuffer, vertexCount);
#endif
}
// In some really unfortunate scenarios (eg Android Studio emulator), we don't have access to glDrawRangeElementsBaseVertex
// So we need to subtract the base vertex index from every index in the index buffer ourselves
// This is not really common, so we do it without SIMD for the moment, just to be able to run on Android Studio
template <bool useShortIndices>
void subtractBaseIndex(u8* indexBuffer, u32 indexCount, u16 baseIndex) {
// Calculate the minimum and maximum indices used in the index buffer, so we'll only upload them
if constexpr (useShortIndices) {
u16* indexBuffer16 = reinterpret_cast<u16*>(indexBuffer);
for (u32 i = 0; i < indexCount; i++) {
indexBuffer16[i] -= baseIndex;
}
} else {
u8 baseIndex8 = u8(baseIndex);
for (u32 i = 0; i < indexCount; i++) {
indexBuffer[i] -= baseIndex8;
}
}
}
} // namespace PICA::IndexBuffer

30
src/core/renderer_gl/renderer_gl.cpp
View file

@ -8,6 +8,7 @@
#include "PICA/float_types.hpp"
#include "PICA/gpu.hpp"
#include "PICA/pica_frag_uniforms.hpp"
#include "PICA/pica_simd.hpp"
#include "PICA/regs.hpp"
#include "PICA/shader_decompiler.hpp"
#include "config.hpp"
@ -192,8 +193,8 @@ void RendererGL::initGraphicsContextInternal() {
reset();
// Populate our driver info structure
driverInfo.supportsExtFbFetch = GLAD_GL_EXT_shader_framebuffer_fetch != 0;
driverInfo.supportsArmFbFetch = GLAD_GL_ARM_shader_framebuffer_fetch != 0;
driverInfo.supportsExtFbFetch = (GLAD_GL_EXT_shader_framebuffer_fetch != 0);
driverInfo.supportsArmFbFetch = (GLAD_GL_ARM_shader_framebuffer_fetch != 0);
// Initialize the default vertex shader used with shadergen
std::string defaultShadergenVSSource = fragShaderGen.getDefaultVertexShader();
@ -519,10 +520,20 @@ void RendererGL::drawVertices(PICA::PrimType primType, std::span<const Vertex> v
if (performIndexedRender) {
// When doing indexed rendering, use glDrawRangeElementsBaseVertex to issue the indexed draw
hwIndexBuffer->Bind();
glDrawRangeElementsBaseVertex(
primitiveTopology, minimumIndex, maximumIndex, GLsizei(vertices.size()), usingShortIndices ? GL_UNSIGNED_SHORT : GL_UNSIGNED_BYTE,
hwIndexBufferOffset, -GLint(minimumIndex)
);
if (glDrawRangeElementsBaseVertex != nullptr) [[likely]] {
glDrawRangeElementsBaseVertex(
primitiveTopology, minimumIndex, maximumIndex, GLsizei(vertices.size()), usingShortIndices ? GL_UNSIGNED_SHORT : GL_UNSIGNED_BYTE,
hwIndexBufferOffset, -GLint(minimumIndex)
);
} else {
// If glDrawRangeElementsBaseVertex is not available then prepareForDraw will have subtracted the base vertex from the index buffer
// for us, so just use glDrawRangeElements
glDrawRangeElements(
primitiveTopology, 0, GLint(maximumIndex - minimumIndex), GLsizei(vertices.size()),
usingShortIndices ? GL_UNSIGNED_SHORT : GL_UNSIGNED_BYTE, hwIndexBufferOffset
);
}
} else {
// When doing non-indexed rendering, just use glDrawArrays
OpenGL::draw(primitiveTopology, GLsizei(vertices.size()));
@ -1170,6 +1181,13 @@ void RendererGL::accelerateVertexUpload(ShaderUnit& shaderUnit, PICA::DrawAccele
hwIndexBufferOffset = reinterpret_cast<void*>(usize(indexBufferRes.buffer_offset));
std::memcpy(indexBufferRes.pointer, accel->indexBuffer, indexBufferSize);
// If we don't have glDrawRangeElementsBaseVertex, we must subtract the base index value from our index buffer manually
if (glDrawRangeElementsBaseVertex == nullptr) [[unlikely]] {
const u32 indexCount = regs[PICA::InternalRegs::VertexCountReg];
usingShortIndices ? PICA::IndexBuffer::subtractBaseIndex<true>((u8*)indexBufferRes.pointer, indexCount, accel->minimumIndex)
: PICA::IndexBuffer::subtractBaseIndex<false>((u8*)indexBufferRes.pointer, indexCount, accel->minimumIndex);
}
hwIndexBuffer->Unmap(indexBufferSize);
}