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SDL_RenderGeometry / software: TRIANGLE_GET_TEXTCOORD interpolates up to the max values included, so reduce by 1

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Sylvain 2022-01-02 22:34:56 +01:00
parent 4b112620a3
commit 8622eda9e9
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GPG Key ID: 5F87E02E5BC0939E
1 changed files with 37 additions and 6 deletions
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43
src/render/software/SDL_triangle.c
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@ -119,8 +119,8 @@ void trianglepoint_2_fixedpoint(SDL_Point *a) {
a->y <<= FP_BITS;
}
/* bounding rect of three points */
static void bounding_rect(const SDL_Point *a, const SDL_Point *b, const SDL_Point *c, SDL_Rect *r)
/* bounding rect of three points (in fixed point) */
static void bounding_rect_fixedpoint(const SDL_Point *a, const SDL_Point *b, const SDL_Point *c, SDL_Rect *r)
{
int min_x = SDL_min(a->x, SDL_min(b->x, c->x));
int max_x = SDL_max(a->x, SDL_max(b->x, c->x));
@ -133,6 +133,20 @@ static void bounding_rect(const SDL_Point *a, const SDL_Point *b, const SDL_Poin
r->h = (max_y - min_y) >> FP_BITS;
}
/* bounding rect of three points */
static void bounding_rect(const SDL_Point *a, const SDL_Point *b, const SDL_Point *c, SDL_Rect *r)
{
int min_x = SDL_min(a->x, SDL_min(b->x, c->x));
int max_x = SDL_max(a->x, SDL_max(b->x, c->x));
int min_y = SDL_min(a->y, SDL_min(b->y, c->y));
int max_y = SDL_max(a->y, SDL_max(b->y, c->y));
r->x = min_x;
r->y = min_y;
r->w = (max_x - min_x);
r->h = (max_y - min_y);
}
/* Triangle rendering, using Barycentric coordinates (w0, w1, w2)
*
* The cross product isn't computed from scratch at each iteration,
@ -232,7 +246,7 @@ int SDL_SW_FillTriangle(SDL_Surface *dst, SDL_Point *d0, SDL_Point *d1, SDL_Poin
}
}
bounding_rect(d0, d1, d2, &dstrect);
bounding_rect_fixedpoint(d0, d1, d2, &dstrect);
{
/* Clip triangle rect with surface rect */
@ -438,7 +452,6 @@ int SDL_SW_BlitTriangle(
SDL_BlendMode blend;
SDL_Rect srcrect;
SDL_Rect dstrect;
SDL_Point s2_x_area;
@ -495,11 +508,29 @@ int SDL_SW_BlitTriangle(
is_uniform = COLOR_EQ(c0, c1) && COLOR_EQ(c1, c2);
bounding_rect(s0, s1, s2, &srcrect);
bounding_rect(d0, d1, d2, &dstrect);
bounding_rect_fixedpoint(d0, d1, d2, &dstrect);
SDL_GetSurfaceBlendMode(src, &blend);
/* TRIANGLE_GET_TEXTCOORD interpolates up to the max values included, so reduce by 1 */
{
SDL_Rect srcrect;
int maxx, maxy;
bounding_rect(s0, s1, s2, &srcrect);
maxx = srcrect.x + srcrect.w;
maxy = srcrect.y + srcrect.h;
if (srcrect.w > 0) {
if (s0->x == maxx) s0->x--;
if (s1->x == maxx) s1->x--;
if (s2->x == maxx) s2->x--;
}
if (srcrect.h > 0) {
if (s0->y == maxy) s0->y--;
if (s1->y == maxy) s1->y--;
if (s2->y == maxy) s2->y--;
}
}
if (is_uniform) {
// SDL_GetSurfaceColorMod(src, &r, &g, &b);
has_modulation = c0.r != 255 || c0.g != 255 || c0.b != 255 || c0.a != 255;;