From d0f19109185cb67f36b447601d9370a95d0a10bc Mon Sep 17 00:00:00 2001
From: expikr <[EMAIL REDACTED]>
Date: Mon, 28 Oct 2024 10:48:47 +0800
Subject: [PATCH] add SDL_RenderTextureAffine
---
include/SDL3/SDL_render.h | 30 ++++++++++
src/render/SDL_render.c | 117 ++++++++++++++++++++++++++++++++++++++
2 files changed, 147 insertions(+)
diff --git a/include/SDL3/SDL_render.h b/include/SDL3/SDL_render.h
index d76f32cc68e68..3229c295c36ff 100644
--- a/include/SDL3/SDL_render.h
+++ b/include/SDL3/SDL_render.h
@@ -2076,6 +2076,36 @@ extern SDL_DECLSPEC bool SDLCALL SDL_RenderTextureRotated(SDL_Renderer *renderer
double angle, const SDL_FPoint *center,
SDL_FlipMode flip);
+/**
+ * Copy a portion of the source texture to the current rendering target, with
+ * affine transform, at subpixel precision.
+ *
+ * \param renderer the renderer which should copy parts of a texture.
+ * \param texture the source texture.
+ * \param srcrect a pointer to the source rectangle, or NULL for the entire
+ * texture.
+ * \param origin a pointer to a point indicating where the top-left corner of
+ srcrect should be mapped to, or NULL for the rendering
+ target's origin.
+ * \param right a pointer to a point indicating where the top-right corner of
+ srcrect should be mapped to, or NULL for the rendering
+ target's top-right corner.
+ * \param down a pointer to a point indicating where the bottom-left corner
+ of srcrect should be mapped to, or NULL for the rendering
+ target's bottom-left corner.
+ * \returns true on success or false on failure; call SDL_GetError() for more
+ * information.
+ *
+ * \threadsafety You may only call this function from the main thread.
+ *
+ * \since This function is available since SDL 3.0.0.
+ *
+ * \sa SDL_RenderTexture
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_RenderTextureAffine(SDL_Renderer *renderer, SDL_Texture *texture,
+ const SDL_FRect *srcrect, const SDL_FPoint *origin,
+ const SDL_FPoint *right, const SDL_FPoint *down);
+
/**
* Tile a portion of the texture to the current rendering target at subpixel
* precision.
diff --git a/src/render/SDL_render.c b/src/render/SDL_render.c
index 93d3aee46010b..a742700c250ae 100644
--- a/src/render/SDL_render.c
+++ b/src/render/SDL_render.c
@@ -3918,6 +3918,123 @@ bool SDL_RenderTexture(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_F
return SDL_RenderTextureInternal(renderer, texture, &real_srcrect, &real_dstrect);
}
+bool SDL_RenderTextureAffine(SDL_Renderer *renderer, SDL_Texture *texture,
+ const SDL_FRect *srcrect, const SDL_FPoint *origin, const SDL_FPoint *right, const SDL_FPoint *down)
+{
+ SDL_FRect real_srcrect;
+ SDL_FRect real_dstrect;
+ bool result;
+
+ CHECK_RENDERER_MAGIC(renderer, false);
+ CHECK_TEXTURE_MAGIC(texture, false);
+
+ if (renderer != texture->renderer) {
+ return SDL_SetError("Texture was not created with this renderer");
+ }
+ if (!renderer->QueueCopyEx && !renderer->QueueGeometry) {
+ return SDL_SetError("Renderer does not support RenderCopyEx");
+ }
+
+#if DONT_DRAW_WHILE_HIDDEN
+ // Don't draw while we're hidden
+ if (renderer->hidden) {
+ return true;
+ }
+#endif
+
+ real_srcrect.x = 0.0f;
+ real_srcrect.y = 0.0f;
+ real_srcrect.w = (float)texture->w;
+ real_srcrect.h = (float)texture->h;
+ if (srcrect) {
+ if (!SDL_GetRectIntersectionFloat(srcrect, &real_srcrect, &real_srcrect)) {
+ return true;
+ }
+ }
+
+ GetRenderViewportSize(renderer, &real_dstrect);
+
+ if (texture->native) {
+ texture = texture->native;
+ }
+
+ texture->last_command_generation = renderer->render_command_generation;
+
+ const float scale_x = renderer->view->current_scale.x;
+ const float scale_y = renderer->view->current_scale.y;
+
+ {
+ float xy[8];
+ const int xy_stride = 2 * sizeof(float);
+ float uv[8];
+ const int uv_stride = 2 * sizeof(float);
+ const int num_vertices = 4;
+ const int *indices = rect_index_order;
+ const int num_indices = 6;
+ const int size_indices = 4;
+
+ float minu = real_srcrect.x / texture->w;
+ float minv = real_srcrect.y / texture->h;
+ float maxu = (real_srcrect.x + real_srcrect.w) / texture->w;
+ float maxv = (real_srcrect.y + real_srcrect.h) / texture->h;
+
+ uv[0] = minu;
+ uv[1] = minv;
+ uv[2] = maxu;
+ uv[3] = minv;
+ uv[4] = maxu;
+ uv[5] = maxv;
+ uv[6] = minu;
+ uv[7] = maxv;
+
+ // (minx, miny)
+ if (origin) {
+ xy[0] = origin->x;
+ xy[1] = origin->y;
+ } else {
+ xy[0] = real_dstrect.x;
+ xy[1] = real_dstrect.y;
+ }
+
+ // (maxx, miny)
+ if (right) {
+ xy[2] = right->x;
+ xy[3] = right->y;
+ } else {
+ xy[2] = real_dstrect.x + real_dstrect.w;
+ xy[3] = real_dstrect.y;
+ }
+
+ // (minx, maxy)
+ if (down) {
+ xy[6] = down->x;
+ xy[7] = down->y;
+ } else {
+ xy[6] = real_dstrect.x;
+ xy[7] = real_dstrect.y + real_dstrect.h;
+ }
+
+ // (maxx, maxy)
+ if (origin || right || down) {
+ xy[4] = xy[2] + xy[6] - xy[0];
+ xy[5] = xy[3] + xy[7] - xy[1];
+ } else {
+ xy[4] = real_dstrect.x + real_dstrect.w;
+ xy[5] = real_dstrect.y + real_dstrect.h;
+ }
+
+ result = QueueCmdGeometry(
+ renderer, texture,
+ xy, xy_stride,
+ &texture->color, 0 /* color_stride */,
+ uv, uv_stride,
+ num_vertices, indices, num_indices, size_indices,
+ scale_x, scale_y, SDL_TEXTURE_ADDRESS_CLAMP
+ );
+ }
+ return result;
+}
+
bool SDL_RenderTextureRotated(SDL_Renderer *renderer, SDL_Texture *texture,
const SDL_FRect *srcrect, const SDL_FRect *dstrect,
const double angle, const SDL_FPoint *center, const SDL_FlipMode flip)