Optimise perspective divide assuming W is always positive

This commit is contained in:
Luke Benstead 2022-11-05 20:28:24 +00:00
parent aa875ae4d1
commit 5296f5c79c

View File

@ -47,11 +47,12 @@ void SceneListBegin(GPUList list) {
pvr_list_begin(list);
}
__attribute__((optimize("O3", "fast-math")))
GL_FORCE_INLINE float _glFastInvert(float x) {
const float sgn = (x > 0) - (x < 0);
return sgn * (1.f / __builtin_sqrtf(x * x));
return (1.f / __builtin_sqrtf(x * x));
}
__attribute__((optimize("O3", "fast-math")))
GL_FORCE_INLINE void _glPerspectiveDivideVertex(Vertex* vertex, const float h) {
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
avoid a divide by zero.
*/
if(unlikely(vertex->w == 1.0f)) {
vertex->xyz[2] = _glFastInvert(1.0001f + vertex->xyz[2]);
} else {
vertex->xyz[2] = f;
}
vertex->xyz[2] = (vertex->w == 1.0f) ? _glFastInvert(1.0001f + vertex->xyz[2]) : f;
}
static uint32_t *d; // SQ target