From 86200d1203f3739d10deb6b72f1ce643b7c1bfb2 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Mon, 21 Jul 2025 10:03:49 -0700
Subject: [PATCH] Fixed clamp texture address mode in software renderer
---
src/render/SDL_render.c | 16 ++++++++
src/render/software/SDL_triangle.c | 64 +++++++-----------------------
2 files changed, 30 insertions(+), 50 deletions(-)
diff --git a/src/render/SDL_render.c b/src/render/SDL_render.c
index d66a8987c62a6..a3351ce1fc440 100644
--- a/src/render/SDL_render.c
+++ b/src/render/SDL_render.c
@@ -5001,6 +5001,22 @@ static bool SDLCALL SDL_SW_RenderGeometryRaw(SDL_Renderer *renderer,
}
}
+ // Check if UVs within range
+ if (is_quad) {
+ const float *uv0_ = (const float *)((const char *)uv + A * color_stride);
+ const float *uv1_ = (const float *)((const char *)uv + B * color_stride);
+ const float *uv2_ = (const float *)((const char *)uv + C * color_stride);
+ const float *uv3_ = (const float *)((const char *)uv + C2 * color_stride);
+ if (uv0_[0] >= 0.0f && uv0_[0] <= 1.0f &&
+ uv1_[0] >= 0.0f && uv1_[0] <= 1.0f &&
+ uv2_[0] >= 0.0f && uv2_[0] <= 1.0f &&
+ uv3_[0] >= 0.0f && uv3_[0] <= 1.0f) {
+ // ok
+ } else {
+ is_quad = 0;
+ }
+ }
+
// Start rendering rect
if (is_quad) {
SDL_FRect s;
diff --git a/src/render/software/SDL_triangle.c b/src/render/software/SDL_triangle.c
index 2a4d150b884e2..265dc46c81d0f 100644
--- a/src/render/software/SDL_triangle.c
+++ b/src/render/software/SDL_triangle.c
@@ -149,19 +149,6 @@ static void bounding_rect_fixedpoint(const SDL_Point *a, const SDL_Point *b, con
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,
@@ -186,13 +173,25 @@ static void bounding_rect(const SDL_Point *a, const SDL_Point *b, const SDL_Poin
#define TRIANGLE_GET_TEXTCOORD \
int srcx = (int)(((Sint64)w0 * s2s0_x + (Sint64)w1 * s2s1_x + s2_x_area.x) / area); \
int srcy = (int)(((Sint64)w0 * s2s0_y + (Sint64)w1 * s2s1_y + s2_x_area.y) / area); \
- if (texture_address_mode_u == SDL_TEXTURE_ADDRESS_WRAP) { \
+ if (texture_address_mode_u == SDL_TEXTURE_ADDRESS_CLAMP) { \
+ if (srcx < 0) { \
+ srcx = 0; \
+ } else if (srcx >= src_surface->w) { \
+ srcx = src_surface->w - 1; \
+ } \
+ } else if (texture_address_mode_u == SDL_TEXTURE_ADDRESS_WRAP) { \
srcx %= src_surface->w; \
if (srcx < 0) { \
srcx += (src_surface->w - 1); \
} \
} \
- if (texture_address_mode_v == SDL_TEXTURE_ADDRESS_WRAP) { \
+ if (texture_address_mode_v == SDL_TEXTURE_ADDRESS_CLAMP) { \
+ if (srcy < 0) { \
+ srcy = 0; \
+ } else if (srcy >= src_surface->h) { \
+ srcy = src_surface->h - 1; \
+ } \
+ } else if (texture_address_mode_v == SDL_TEXTURE_ADDRESS_WRAP) { \
srcy %= src_surface->h; \
if (srcy < 0) { \
srcy += (src_surface->h - 1); \
@@ -543,41 +542,6 @@ bool SDL_SW_BlitTriangle(
SDL_GetSurfaceBlendMode(src, &blend);
- // TRIANGLE_GET_TEXTCOORD interpolates up to the max values included, so reduce by 1
- if (texture_address_mode_u == SDL_TEXTURE_ADDRESS_CLAMP ||
- texture_address_mode_v == SDL_TEXTURE_ADDRESS_CLAMP) {
- SDL_Rect srcrect;
- bounding_rect(s0, s1, s2, &srcrect);
- if (texture_address_mode_u == SDL_TEXTURE_ADDRESS_CLAMP) {
- int maxx = srcrect.x + srcrect.w;
- if (srcrect.w > 0) {
- if (s0->x == maxx) {
- s0->x--;
- }
- if (s1->x == maxx) {
- s1->x--;
- }
- if (s2->x == maxx) {
- s2->x--;
- }
- }
- }
- if (texture_address_mode_v == SDL_TEXTURE_ADDRESS_CLAMP) {
- int maxy = srcrect.y + srcrect.h;
- 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;