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software: Correctly track viewport and cliprect.
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Fixes Bugzilla #4457.
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@icculus
icculus committed Jun 11, 2019
1 parent a2f2b73 commit 04fedce
Showing 1 changed file with 46 additions and 19 deletions.
65 changes: 46 additions & 19 deletions src/render/software/SDL_render_sw.c
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Expand Up @@ -37,6 +37,13 @@

/* SDL surface based renderer implementation */

typedef struct
{
const SDL_Rect *viewport;
const SDL_Rect *cliprect;
SDL_bool surface_cliprect_dirty;
} SW_DrawStateCache;

typedef struct
{
SDL_Surface *surface;
Expand Down Expand Up @@ -568,44 +575,59 @@ PrepTextureForCopy(const SDL_RenderCommand *cmd)
SDL_SetSurfaceBlendMode(surface, blend);
}

static void
SetDrawState(SDL_Surface *surface, SW_DrawStateCache *drawstate)
{
if (drawstate->surface_cliprect_dirty) {
const SDL_Rect *viewport = drawstate->viewport;
const SDL_Rect *cliprect = drawstate->cliprect;
SDL_assert(viewport != NULL); /* the higher level should have forced a SDL_RENDERCMD_SETVIEWPORT */

if (cliprect != NULL) {
SDL_Rect clip_rect;
clip_rect.x = cliprect->x + viewport->x;
clip_rect.y = cliprect->y + viewport->y;
clip_rect.w = cliprect->w;
clip_rect.h = cliprect->h;
SDL_IntersectRect(viewport, &clip_rect, &clip_rect);
SDL_SetClipRect(surface, &clip_rect);
} else {
SDL_SetClipRect(surface, drawstate->viewport);
}
drawstate->surface_cliprect_dirty = SDL_FALSE;
}
}

static int
SW_RunCommandQueue(SDL_Renderer * renderer, SDL_RenderCommand *cmd, void *vertices, size_t vertsize)
{
SW_RenderData *data = (SW_RenderData *) renderer->driverdata;
SDL_Surface *surface = SW_ActivateRenderer(renderer);
const SDL_Rect *viewport = NULL;
const SDL_Rect *cliprect = NULL;
SW_DrawStateCache drawstate;

if (!surface) {
return -1;
}

drawstate.viewport = NULL;
drawstate.cliprect = NULL;
drawstate.surface_cliprect_dirty = SDL_TRUE;

while (cmd) {
switch (cmd->command) {
case SDL_RENDERCMD_SETDRAWCOLOR: {
break; /* Not used in this backend. */
}

case SDL_RENDERCMD_SETVIEWPORT: {
viewport = &cmd->data.viewport.rect;
SDL_SetClipRect(data->surface, viewport);
drawstate.viewport = &cmd->data.viewport.rect;
drawstate.surface_cliprect_dirty = SDL_TRUE;
break;
}

case SDL_RENDERCMD_SETCLIPRECT: {
SDL_assert(viewport != NULL);
cliprect = cmd->data.cliprect.enabled ? &cmd->data.cliprect.rect : NULL;
if (cliprect) {
SDL_Rect clip_rect;
clip_rect.x = cliprect->x + viewport->x;
clip_rect.y = cliprect->y + viewport->y;
clip_rect.w = cliprect->w;
clip_rect.h = cliprect->h;
SDL_IntersectRect(viewport, &clip_rect, &clip_rect);
SDL_SetClipRect(surface, &clip_rect);
} else {
SDL_SetClipRect(surface, viewport);
}
drawstate.cliprect = cmd->data.cliprect.enabled ? &cmd->data.cliprect.rect : NULL;
drawstate.surface_cliprect_dirty = SDL_TRUE;
break;
}

Expand All @@ -614,11 +636,10 @@ SW_RunCommandQueue(SDL_Renderer * renderer, SDL_RenderCommand *cmd, void *vertic
const Uint8 g = cmd->data.color.g;
const Uint8 b = cmd->data.color.b;
const Uint8 a = cmd->data.color.a;
const SDL_Rect clip_rect = surface->clip_rect;
/* By definition the clear ignores the clip rect */
SDL_SetClipRect(surface, NULL);
SDL_FillRect(surface, NULL, SDL_MapRGBA(surface->format, r, g, b, a));
SDL_SetClipRect(surface, &clip_rect);
drawstate.surface_cliprect_dirty = SDL_TRUE;
break;
}

Expand All @@ -630,6 +651,7 @@ SW_RunCommandQueue(SDL_Renderer * renderer, SDL_RenderCommand *cmd, void *vertic
const int count = (int) cmd->data.draw.count;
const SDL_Point *verts = (SDL_Point *) (((Uint8 *) vertices) + cmd->data.draw.first);
const SDL_BlendMode blend = cmd->data.draw.blend;
SetDrawState(surface, &drawstate);
if (blend == SDL_BLENDMODE_NONE) {
SDL_DrawPoints(surface, verts, count, SDL_MapRGBA(surface->format, r, g, b, a));
} else {
Expand All @@ -646,6 +668,7 @@ SW_RunCommandQueue(SDL_Renderer * renderer, SDL_RenderCommand *cmd, void *vertic
const int count = (int) cmd->data.draw.count;
const SDL_Point *verts = (SDL_Point *) (((Uint8 *) vertices) + cmd->data.draw.first);
const SDL_BlendMode blend = cmd->data.draw.blend;
SetDrawState(surface, &drawstate);
if (blend == SDL_BLENDMODE_NONE) {
SDL_DrawLines(surface, verts, count, SDL_MapRGBA(surface->format, r, g, b, a));
} else {
Expand All @@ -662,6 +685,7 @@ SW_RunCommandQueue(SDL_Renderer * renderer, SDL_RenderCommand *cmd, void *vertic
const int count = (int) cmd->data.draw.count;
const SDL_Rect *verts = (SDL_Rect *) (((Uint8 *) vertices) + cmd->data.draw.first);
const SDL_BlendMode blend = cmd->data.draw.blend;
SetDrawState(surface, &drawstate);
if (blend == SDL_BLENDMODE_NONE) {
SDL_FillRects(surface, verts, count, SDL_MapRGBA(surface->format, r, g, b, a));
} else {
Expand All @@ -677,6 +701,8 @@ SW_RunCommandQueue(SDL_Renderer * renderer, SDL_RenderCommand *cmd, void *vertic
SDL_Texture *texture = cmd->data.draw.texture;
SDL_Surface *src = (SDL_Surface *) texture->driverdata;

SetDrawState(surface, &drawstate);

PrepTextureForCopy(cmd);

if ( srcrect->w == dstrect->w && srcrect->h == dstrect->h ) {
Expand All @@ -693,6 +719,7 @@ SW_RunCommandQueue(SDL_Renderer * renderer, SDL_RenderCommand *cmd, void *vertic

case SDL_RENDERCMD_COPY_EX: {
const CopyExData *copydata = (CopyExData *) (((Uint8 *) vertices) + cmd->data.draw.first);
SetDrawState(surface, &drawstate);
PrepTextureForCopy(cmd);
SW_RenderCopyEx(renderer, surface, cmd->data.draw.texture, &copydata->srcrect,
&copydata->dstrect, copydata->angle, &copydata->center, copydata->flip);
Expand Down

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