Port #12581 to SDL2

This fixes undefined behavior resulting from adding offsets to nullptr.
This commit is contained in:
Derek Schuff
2025-05-01 23:19:50 +00:00
committed by Sam Lantinga
parent 2442c85cb8
commit a220e7c422

View File

@@ -975,8 +975,8 @@ static int SetDrawState(GLES2_RenderData *data, const SDL_RenderCommand *cmd, co
}
if (texture) {
SDL_Vertex *verts = (SDL_Vertex *)(((Uint8 *)vertices) + cmd->data.draw.first);
data->glVertexAttribPointer(GLES2_ATTRIBUTE_TEXCOORD, 2, GL_FLOAT, GL_FALSE, stride, (const GLvoid *)&verts->tex_coord);
uintptr_t base = (uintptr_t)vertices + cmd->data.draw.first; // address of first vertex, or base offset when using VBOs.
data->glVertexAttribPointer(GLES2_ATTRIBUTE_TEXCOORD, 2, GL_FLOAT, GL_FALSE, stride, (const GLvoid *)(base + offsetof(SDL_Vertex, tex_coord)));
}
if (GLES2_SelectProgram(data, imgsrc, texture ? texture->w : 0, texture ? texture->h : 0) < 0) {
@@ -1009,9 +1009,9 @@ static int SetDrawState(GLES2_RenderData *data, const SDL_RenderCommand *cmd, co
/* all drawing commands use this */
{
SDL_VertexSolid *verts = (SDL_VertexSolid *)(((Uint8 *)vertices) + cmd->data.draw.first);
data->glVertexAttribPointer(GLES2_ATTRIBUTE_POSITION, 2, GL_FLOAT, GL_FALSE, stride, (const GLvoid *)&verts->position);
data->glVertexAttribPointer(GLES2_ATTRIBUTE_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE /* Normalized */, stride, (const GLvoid *)&verts->color);
uintptr_t base = (uintptr_t)vertices + cmd->data.draw.first; // address of first vertex, or base offset when using VBOs.
data->glVertexAttribPointer(GLES2_ATTRIBUTE_POSITION, 2, GL_FLOAT, GL_FALSE, stride, (const GLvoid *)(base + offsetof(SDL_VertexSolid, position)));
data->glVertexAttribPointer(GLES2_ATTRIBUTE_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE /* Normalized */, stride, (const GLvoid *)(base + offsetof(SDL_VertexSolid, color)));
}
return 0;
@@ -1200,7 +1200,8 @@ static int GLES2_RunCommandQueue(SDL_Renderer *renderer, SDL_RenderCommand *cmd,
if (data->current_vertex_buffer >= SDL_arraysize(data->vertex_buffers)) {
data->current_vertex_buffer = 0;
}
vertices = NULL; /* attrib pointers will be offsets into the VBO. */
// attrib pointers will be offsets into the VBO.
vertices = (void *)(uintptr_t)0; // must be the exact value 0, not NULL (the representation of NULL is not guaranteed to be 0).
#endif
while (cmd) {