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Implement true clipping on the near plane

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This commit is contained in:
Luke Benstead 2020-03-20 21:15:05 +00:00
parent 03bc758be7
commit f2a39a4229
1 changed files with 18 additions and 10 deletions
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28
GL/clip.c
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@ -23,21 +23,21 @@ void _glEnableClipping(unsigned char v) {
ZCLIP_ENABLED = v;
}
void _glClipLineToNearZ(const Vertex* v1, const Vertex* v2, Vertex* vout, float* t) __attribute__((optimize("fast-math")));
void _glClipLineToNearZ(const Vertex* v1, const Vertex* v2, Vertex* vout, float* t) {
void inline _glClipLineToNearZ(const Vertex* v1, const Vertex* v2, Vertex* vout, float* t) {
const float d0 = v1->w + v1->xyz[2];
const float d1 = v2->w + v2->xyz[2];
/* 0.2f is the zclip distance set by KOS in the PVR registers. This is weird and
* no-one yet knows why. */
const float NEAR_PLANE = NEAR_PLANE_DISTANCE + 0.2f;
*t = d0 / (d0 - d1);
*t = (NEAR_PLANE - v1->w) / (v2->w - v1->w);
float vec [] = {v2->xyz[0] - v1->xyz[0], v2->xyz[1] - v1->xyz[1], v2->xyz[2] - v1->xyz[2]};
const float vec [] = {
v2->xyz[0] - v1->xyz[0],
v2->xyz[1] - v1->xyz[1],
v2->xyz[2] - v1->xyz[2]
};
vout->xyz[0] = MATH_fmac(vec[0], (*t), v1->xyz[0]);
vout->xyz[1] = MATH_fmac(vec[1], (*t), v1->xyz[1]);
vout->xyz[2] = MATH_fmac(vec[2], (*t), v1->xyz[2]);
}
GL_FORCE_INLINE void interpolateFloat(const float v1, const float v2, const float t, float* out) {
@ -250,7 +250,15 @@ void _glClipTriangleStrip(SubmissionTarget* target, uint8_t fladeShade) {
vi2 = v2 - start;
vi3 = v3 - start;
uint8_t visible = ((v1->w > 0) ? 4 : 0) | ((v2->w > 0) ? 2 : 0) | ((v3->w > 0) ? 1 : 0);
/*
* A vertex is visible if it's in front of the camera (W > 0)
* and it's in front of the near plane (Z > -W)
*/
uint8_t visible = (
((v1->w > 0 && v1->xyz[2] > -v1->w) ? 4 : 0) |
((v2->w > 0 && v2->xyz[2] > -v2->w) ? 2 : 0) |
((v3->w > 0 && v3->xyz[2] > -v3->w) ? 1 : 0)
);
switch(visible) {
case B111: