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Fix the majority of clipping bugs

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This commit is contained in:
Luke Benstead 2020-11-02 20:53:26 +00:00
parent 174483941e
commit 85c60ffc5a
1 changed files with 38 additions and 24 deletions
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62
GL/flush.c
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@ -43,8 +43,8 @@ GL_FORCE_INLINE float _glClipLineToNearZ(const Vertex* v1, const Vertex* v2, Ver
/* We need to shift 't' a little, to avoid the possibility that a
* rounding error leaves the new vertex behind the near plane. We shift
* according to the direction we're clipping across the plane */
const float epsilon = (d0 < d1) ? 0.0000001 : -0.0000001;
float t = MATH_Fast_Divide(d0, (d0 - d1))+ epsilon;
const float epsilon = (d0 < d1) ? 0.000001 : -0.000001;
float t = MATH_Fast_Divide(d0, (d0 - d1)) + epsilon;
vout->xyz[0] = MATH_fmac(v2->xyz[0] - v1->xyz[0], t, v1->xyz[0]);
vout->xyz[1] = MATH_fmac(v2->xyz[1] - v1->xyz[1], t, v1->xyz[1]);
@ -96,6 +96,11 @@ static Vertex* interpolate_vertex(const Vertex* v0, const Vertex* v1, Vertex* ou
/* If v0 is in front of the near plane, and v1 is behind the near plane, this
* generates a vertex *on* the near plane */
CLIP_TO_PLANE(v0, v1);
/* We can't have a W == 0, or we'll get a divide by zero. If we have a W < 0
* then our clipping has gone wrong! */
assert(out->w > 0.0f);
return out;
}
@ -179,7 +184,7 @@ static ListIterator* finish_clip(ListIterator* it) {
static ListIterator* clip100(ListIterator* it) {
#if CLIP_DEBUG
printf("clip100\n");
printf(">> clip100\n");
#endif
TRACE();
@ -215,46 +220,51 @@ static ListIterator* clip100(ListIterator* it) {
assert(isVertex(gen3));
it->active = gen1;
it->stack_idx--;
return finish_clip(it);
}
static ListIterator* clip110(ListIterator* it) {
#if CLIP_DEBUG
printf("clip110\n");
printf(">> clip110\n");
#endif
TRACE();
/* First two visible. so we need to create 2 new vertices from
* A -> C, and B -> C. */
Vertex* gen4 = push_stack(it);
Vertex* gen3 = push_stack(it);
Vertex* gen2 = push_stack(it);
Vertex* gen1 = push_stack(it);
Vertex* cpy = push_stack(it);
gen1->flags = PVR_CMD_VERTEX;
gen2->flags = PVR_CMD_VERTEX_EOL;
gen2->flags = PVR_CMD_VERTEX;
gen3->flags = PVR_CMD_VERTEX;
gen4->flags = PVR_CMD_VERTEX_EOL;
interpolate_vertex(it->triangle[0], it->triangle[2], gen1);
interpolate_vertex(it->triangle[1], it->triangle[2], gen2);
*gen1 = *it->triangle[0];
*gen2 = *it->triangle[1];
interpolate_vertex(it->triangle[0], it->triangle[2], gen3);
interpolate_vertex(it->triangle[1], it->triangle[2], gen4);
assert(isVisible(gen1));
assert(isVisible(gen2));
assert(isVertex(gen1));
assert(isVertex(gen2));
/* We copy vertex B, so that things are returned in order */
*cpy = *it->triangle[1];
/* Return A */
it->active = it->triangle[0];
it->active = gen1;
it->stack_idx--;
return finish_clip(it);
}
static ListIterator* clip101(ListIterator* it) {
#if CLIP_DEBUG
printf("clip101\n");
printf(">> clip101\n");
#endif
TRACE();
@ -268,7 +278,7 @@ static ListIterator* clip101(ListIterator* it) {
/* First and last need to be the same*/
*gen1 = *it->triangle[0];
*gen4 = *it->triangle[2];
*gen3 = *it->triangle[2];
gen1->flags = PVR_CMD_VERTEX;
gen2->flags = PVR_CMD_VERTEX;
@ -276,16 +286,17 @@ static ListIterator* clip101(ListIterator* it) {
gen4->flags = PVR_CMD_VERTEX_EOL; /* 4 is now last in the list */
interpolate_vertex(it->triangle[0], it->triangle[1], gen2);
interpolate_vertex(it->triangle[1], it->triangle[2], gen3);
interpolate_vertex(it->triangle[1], it->triangle[2], gen4);
it->active = it->triangle[0];
it->active = gen1;
it->stack_idx--;
return finish_clip(it);
}
static ListIterator* clip011(ListIterator* it) {
#if CLIP_DEBUG
printf("clip011\n");
printf(">> clip011\n");
#endif
TRACE();
@ -305,16 +316,17 @@ static ListIterator* clip011(ListIterator* it) {
gen4->flags = PVR_CMD_VERTEX_EOL; /* 4 is now last in the list */
interpolate_vertex(it->triangle[0], it->triangle[1], gen1);
interpolate_vertex(it->triangle[2], it->triangle[0], gen2);
interpolate_vertex(it->triangle[0], it->triangle[2], gen2);
it->active = it->triangle[0];
it->active = gen1;
it->stack_idx--;
return finish_clip(it);
}
static ListIterator* clip001(ListIterator* it) {
#if CLIP_DEBUG
printf("clip001\n");
printf(">> clip001\n");
#endif
TRACE();
@ -331,16 +343,17 @@ static ListIterator* clip001(ListIterator* it) {
gen3->flags = PVR_CMD_VERTEX_EOL;
interpolate_vertex(it->triangle[0], it->triangle[2], gen1);
interpolate_vertex(it->triangle[2], it->triangle[1], gen2);
interpolate_vertex(it->triangle[1], it->triangle[2], gen2);
it->active = it->triangle[0];
it->active = gen1;
it->stack_idx--;
return finish_clip(it);
}
static ListIterator* clip010(ListIterator* it) {
#if CLIP_DEBUG
printf("clip010\n");
printf(">> clip010\n");
#endif
TRACE();
@ -359,7 +372,8 @@ static ListIterator* clip010(ListIterator* it) {
interpolate_vertex(it->triangle[0], it->triangle[1], gen1);
interpolate_vertex(it->triangle[1], it->triangle[2], gen3);
it->active = it->triangle[0];
it->active = gen1;
it->stack_idx--;
return finish_clip(it);
}