render: simplify vertex and uniform data allocation. Improves performance of various SDL_Render functions (bug #4764).
diff --git a/src/render/SDL_render.c b/src/render/SDL_render.c
index 5b0c1bf..6e7ec61 100644
--- a/src/render/SDL_render.c
+++ b/src/render/SDL_render.c
@@ -202,8 +202,6 @@
static int
FlushRenderCommands(SDL_Renderer *renderer)
{
- SDL_AllocVertGap *prevgap = &renderer->vertex_data_gaps;
- SDL_AllocVertGap *gap = prevgap;
int retval;
SDL_assert((renderer->render_commands == NULL) == (renderer->render_commands_tail == NULL));
@@ -217,14 +215,6 @@
retval = renderer->RunCommandQueue(renderer, renderer->render_commands, renderer->vertex_data, renderer->vertex_data_used);
- while (gap) {
- prevgap = gap;
- gap = gap->next;
- }
- prevgap->next = renderer->vertex_data_gaps_pool;
- renderer->vertex_data_gaps_pool = renderer->vertex_data_gaps.next;
- renderer->vertex_data_gaps.next = NULL;
-
/* Move the whole render command queue to the unused pool so we can reuse them next time. */
if (renderer->render_commands_tail != NULL) {
renderer->render_commands_tail->next = renderer->render_commands_pool;
@@ -263,79 +253,23 @@
return FlushRenderCommands(renderer);
}
-static SDL_AllocVertGap *
-AllocateVertexGap(SDL_Renderer *renderer)
-{
- SDL_AllocVertGap *retval = renderer->vertex_data_gaps_pool;
- if (retval) {
- renderer->vertex_data_gaps_pool = retval->next;
- retval->next = NULL;
- } else {
- retval = (SDL_AllocVertGap *) SDL_malloc(sizeof (SDL_AllocVertGap));
- if (!retval) {
- SDL_OutOfMemory();
- }
- }
- return retval;
-}
-
-
void *
SDL_AllocateRenderVertices(SDL_Renderer *renderer, const size_t numbytes, const size_t alignment, size_t *offset)
{
const size_t needed = renderer->vertex_data_used + numbytes + alignment;
- size_t aligner, aligned;
- void *retval;
+ size_t current_offset = renderer->vertex_data_used;
- SDL_AllocVertGap *prevgap = &renderer->vertex_data_gaps;
- SDL_AllocVertGap *gap = prevgap->next;
- while (gap) {
- const size_t gapoffset = gap->offset;
- aligner = (alignment && ((gap->offset % alignment) != 0)) ? (alignment - (gap->offset % alignment)) : 0;
- aligned = gapoffset + aligner;
+ size_t aligner = (alignment && ((current_offset & (alignment - 1)) != 0)) ? (alignment - (current_offset & (alignment - 1))) : 0;
+ size_t aligned = current_offset + aligner;
- /* Can we use this gap? */
- if ((aligner < gap->len) && ((gap->len - aligner) >= numbytes)) {
- /* we either finished this gap off, trimmed the left, trimmed the right, or split it into two gaps. */
- if (gap->len == numbytes) { /* finished it off, remove it */
- SDL_assert(aligned == gapoffset);
- prevgap->next = gap->next;
- gap->next = renderer->vertex_data_gaps_pool;
- renderer->vertex_data_gaps_pool = gap;
- } else if (aligned == gapoffset) { /* trimmed the left */
- gap->offset += numbytes;
- gap->len -= numbytes;
- } else if (((aligned - gapoffset) + numbytes) == gap->len) { /* trimmed the right */
- gap->len -= numbytes;
- } else { /* split into two gaps */
- SDL_AllocVertGap *newgap = AllocateVertexGap(renderer);
- if (!newgap) {
- return NULL;
- }
- newgap->offset = aligned + numbytes;
- newgap->len = gap->len - (aligner + numbytes);
- newgap->next = gap->next;
- // gap->offset doesn't change.
- gap->len = aligner;
- gap->next = newgap;
- }
-
- if (offset) {
- *offset = aligned;
- }
- return ((Uint8 *) renderer->vertex_data) + aligned;
- }
-
- /* Try the next gap */
- prevgap = gap;
- gap = gap->next;
- }
-
- /* no gaps with enough space; get a new piece of the vertex buffer */
- while (needed > renderer->vertex_data_allocation) {
+ if (renderer->vertex_data_allocation < needed) {
const size_t current_allocation = renderer->vertex_data ? renderer->vertex_data_allocation : 1024;
- const size_t newsize = current_allocation * 2;
- void *ptr = SDL_realloc(renderer->vertex_data, newsize);
+ size_t newsize = current_allocation * 2;
+ void *ptr;
+ while (newsize < needed) {
+ newsize *= 2;
+ }
+ ptr = SDL_realloc(renderer->vertex_data, newsize);
if (ptr == NULL) {
SDL_OutOfMemory();
return NULL;
@@ -344,27 +278,13 @@
renderer->vertex_data_allocation = newsize;
}
- aligner = (alignment && ((renderer->vertex_data_used % alignment) != 0)) ? (alignment - (renderer->vertex_data_used % alignment)) : 0;
- aligned = renderer->vertex_data_used + aligner;
-
- retval = ((Uint8 *) renderer->vertex_data) + aligned;
if (offset) {
*offset = aligned;
}
- if (aligner) { /* made a new gap... */
- SDL_AllocVertGap *newgap = AllocateVertexGap(renderer);
- if (newgap) { /* just let it slide as lost space if malloc fails. */
- newgap->offset = renderer->vertex_data_used;
- newgap->len = aligner;
- newgap->next = NULL;
- prevgap->next = newgap;
- }
- }
-
renderer->vertex_data_used += aligner + numbytes;
- return retval;
+ return ((Uint8 *) renderer->vertex_data) + aligned;
}
static SDL_RenderCommand *
@@ -3177,8 +3097,6 @@
SDL_DestroyRenderer(SDL_Renderer * renderer)
{
SDL_RenderCommand *cmd;
- SDL_AllocVertGap *gap;
- SDL_AllocVertGap *nextgap;
CHECK_RENDERER_MAGIC(renderer, );
@@ -3203,16 +3121,6 @@
SDL_free(renderer->vertex_data);
- for (gap = renderer->vertex_data_gaps.next; gap; gap = nextgap) {
- nextgap = gap->next;
- SDL_free(gap);
- }
-
- for (gap = renderer->vertex_data_gaps_pool; gap; gap = nextgap) {
- nextgap = gap->next;
- SDL_free(gap);
- }
-
/* Free existing textures for this renderer */
while (renderer->textures) {
SDL_Texture *tex = renderer->textures; (void) tex;
diff --git a/src/render/SDL_sysrender.h b/src/render/SDL_sysrender.h
index 9386562..dedd642 100644
--- a/src/render/SDL_sysrender.h
+++ b/src/render/SDL_sysrender.h
@@ -110,13 +110,6 @@
struct SDL_RenderCommand *next;
} SDL_RenderCommand;
-typedef struct SDL_AllocVertGap
-{
- size_t offset;
- size_t len;
- struct SDL_AllocVertGap *next;
-} SDL_AllocVertGap;
-
/* Define the SDL renderer structure */
struct SDL_Renderer
@@ -226,8 +219,6 @@
void *vertex_data;
size_t vertex_data_used;
size_t vertex_data_allocation;
- SDL_AllocVertGap vertex_data_gaps;
- SDL_AllocVertGap *vertex_data_gaps_pool;
void *driverdata;
};
