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Optimise perspective divide assuming W is always positive

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This commit is contained in:
Luke Benstead 2022-11-05 20:28:24 +00:00
parent aa875ae4d1
commit 5296f5c79c
1 changed files with 5 additions and 7 deletions
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12
GL/platforms/sh4.c
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@ -47,11 +47,12 @@ void SceneListBegin(GPUList list) {
pvr_list_begin(list); pvr_list_begin(list);
} }
__attribute__((optimize("O3", "fast-math")))
GL_FORCE_INLINE float _glFastInvert(float x) { GL_FORCE_INLINE float _glFastInvert(float x) {
const float sgn = (x > 0) - (x < 0); return (1.f / __builtin_sqrtf(x * x));
return sgn * (1.f / __builtin_sqrtf(x * x));
} }
__attribute__((optimize("O3", "fast-math")))
GL_FORCE_INLINE void _glPerspectiveDivideVertex(Vertex* vertex, const float h) { GL_FORCE_INLINE void _glPerspectiveDivideVertex(Vertex* vertex, const float h) {
const float f = _glFastInvert(vertex->w); const float f = _glFastInvert(vertex->w);
@ -69,11 +70,8 @@ GL_FORCE_INLINE void _glPerspectiveDivideVertex(Vertex* vertex, const float h) {
we add 1.0 to the Z to bring it into range. We add a little extra to we add 1.0 to the Z to bring it into range. We add a little extra to
avoid a divide by zero. avoid a divide by zero.
*/ */
if(unlikely(vertex->w == 1.0f)) {
vertex->xyz[2] = _glFastInvert(1.0001f + vertex->xyz[2]); vertex->xyz[2] = (vertex->w == 1.0f) ? _glFastInvert(1.0001f + vertex->xyz[2]) : f;
} else {
vertex->xyz[2] = f;
}
} }
static uint32_t *d; // SQ target static uint32_t *d; // SQ target