Fixed bug 4914 - Expose SDL_ScaleMode and add SDL_SetTextureScaleMode/SDL_GetTextureScaleMode

Konrad

This was something rather trivial to add, but asked at least several times before (I did google about it as well).

It should be possible to dynamically change scaling mode of the texture. It is actually trivial task, but until now it was only possible with a hint before creating a texture.

I needed it for my game as well, so I took the liberty of writing it myself.

This patch adds following functions:

SDL_SetTextureScaleMode(SDL_Texture * texture, SDL_ScaleMode scaleMode);
SDL_GetTextureScaleMode(SDL_Texture * texture, SDL_ScaleMode *scaleMode);

That way you can change texture scaling on the fly.

include/SDL_render.h

@@ -85,6 +85,16 @@ typedef struct SDL_RendererInfo
     int max_texture_height;     /**< The maximum texture height */
 } SDL_RendererInfo;
 
+/**
+ *  \brief The scaling mode for a texture.
+ */
+typedef enum
+{
+    SDL_ScaleModeNearest, /**< nearest pixel sampling */
+    SDL_ScaleModeLinear,  /**< linear filtering */
+    SDL_ScaleModeBest     /**< anisotropic filtering */
+} SDL_ScaleMode;
+
 /**
  *  \brief The access pattern allowed for a texture.
  */
@@ -366,6 +376,35 @@ extern DECLSPEC int SDLCALL SDL_SetTextureBlendMode(SDL_Texture * texture,
 extern DECLSPEC int SDLCALL SDL_GetTextureBlendMode(SDL_Texture * texture,
                                                     SDL_BlendMode *blendMode);
 
+/**
+ *  \brief Set the scale mode used for texture scale operations.
+ *
+ *  \param texture The texture to update.
+ *  \param scaleMode ::SDL_ScaleMode to use for texture scaling.
+ *
+ *  \return 0 on success, or -1 if the texture is not valid.
+ *
+ *  \note If the scale mode is not supported, the closest supported mode is
+ *        chosen.
+ *
+ *  \sa SDL_GetTextureScaleMode()
+ */
+extern DECLSPEC int SDLCALL SDL_SetTextureScaleMode(SDL_Texture * texture,
+                                                    SDL_ScaleMode scaleMode);
+
+/**
+ *  \brief Get the scale mode used for texture scale operations.
+ *
+ *  \param texture   The texture to query.
+ *  \param scaleMode A pointer filled in with the current scale mode.
+ *
+ *  \return 0 on success, or -1 if the texture is not valid.
+ *
+ *  \sa SDL_SetTextureScaleMode()
+ */
+extern DECLSPEC int SDLCALL SDL_GetTextureScaleMode(SDL_Texture * texture,
+                                                    SDL_ScaleMode *scaleMode);
+
 /**
  *  \brief Update the given texture rectangle with new pixel data.
  *

src/dynapi/SDL_dynapi_overrides.h

@@ -737,3 +737,5 @@
 #define SDL_GameControllerSetPlayerIndex SDL_GameControllerSetPlayerIndex_REAL
 #define SDL_JoystickFromPlayerIndex SDL_JoystickFromPlayerIndex_REAL
 #define SDL_JoystickSetPlayerIndex SDL_JoystickSetPlayerIndex_REAL
+#define SDL_SetTextureScaleMode SDL_SetTextureScaleMode_REAL
+#define SDL_GetTextureScaleMode SDL_GetTextureScaleMode_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -793,3 +793,5 @@ SDL_DYNAPI_PROC(SDL_GameController*,SDL_GameControllerFromPlayerIndex,(int a),(a
 SDL_DYNAPI_PROC(void,SDL_GameControllerSetPlayerIndex,(SDL_GameController *a, int b),(a,b),)
 SDL_DYNAPI_PROC(SDL_Joystick*,SDL_JoystickFromPlayerIndex,(int a),(a),return)
 SDL_DYNAPI_PROC(void,SDL_JoystickSetPlayerIndex,(SDL_Joystick *a, int b),(a,b),)
+SDL_DYNAPI_PROC(int,SDL_SetTextureScaleMode,(SDL_Texture *a, SDL_ScaleMode b),(a,b),return)
+SDL_DYNAPI_PROC(int,SDL_GetTextureScaleMode,(SDL_Texture *a, SDL_ScaleMode *b),(a,b),return)

src/render/SDL_render.c

@@ -1388,6 +1388,33 @@ SDL_GetTextureBlendMode(SDL_Texture * texture, SDL_BlendMode *blendMode)
     return 0;
 }
 
+int
+SDL_SetTextureScaleMode(SDL_Texture * texture, SDL_ScaleMode scaleMode)
+{
+    SDL_Renderer *renderer;
+
+    CHECK_TEXTURE_MAGIC(texture, -1);
+
+    renderer = texture->renderer;
+    renderer->SetTextureScaleMode(renderer, texture, scaleMode);
+    texture->scaleMode = scaleMode;
+    if (texture->native) {
+        return SDL_SetTextureScaleMode(texture->native, scaleMode);
+    }
+    return 0;
+}
+
+int
+SDL_GetTextureScaleMode(SDL_Texture * texture, SDL_ScaleMode *scaleMode)
+{
+    CHECK_TEXTURE_MAGIC(texture, -1);
+
+    if (scaleMode) {
+        *scaleMode = texture->scaleMode;
+    }
+    return 0;
+}
+
 static int
 SDL_UpdateTextureYUV(SDL_Texture * texture, const SDL_Rect * rect,
                      const void *pixels, int pitch)

src/render/SDL_sysrender.h

@@ -32,13 +32,6 @@
 
 typedef struct SDL_RenderDriver SDL_RenderDriver;
 
-typedef enum
-{
-    SDL_ScaleModeNearest,
-    SDL_ScaleModeLinear,
-    SDL_ScaleModeBest
-} SDL_ScaleMode;
-
 /* Define the SDL texture structure */
 struct SDL_Texture
 {
@@ -146,6 +139,7 @@ struct SDL_Renderer
     int (*LockTexture) (SDL_Renderer * renderer, SDL_Texture * texture,
                         const SDL_Rect * rect, void **pixels, int *pitch);
     void (*UnlockTexture) (SDL_Renderer * renderer, SDL_Texture * texture);
+    void (*SetTextureScaleMode) (SDL_Renderer * renderer, SDL_Texture * texture, SDL_ScaleMode scaleMode);
     int (*SetRenderTarget) (SDL_Renderer * renderer, SDL_Texture * texture);
     int (*RenderReadPixels) (SDL_Renderer * renderer, const SDL_Rect * rect,
                              Uint32 format, void * pixels, int pitch);

src/render/direct3d/SDL_render_d3d.c

@@ -722,6 +722,18 @@ D3D_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * texture)
     }
 }
 
+static void
+D3D_SetTextureScaleMode(SDL_Renderer * renderer, SDL_Texture * texture, SDL_ScaleMode scaleMode)
+{
+    D3D_TextureData *texturedata = (D3D_TextureData *)texture->driverdata;
+
+    if (!texturedata) {
+        return;
+    }
+
+    texturedata->scaleMode = (scaleMode == SDL_ScaleModeNearest) ? D3DTEXF_POINT : D3DTEXF_LINEAR;
+}
+
 static int
 D3D_SetRenderTargetInternal(SDL_Renderer * renderer, SDL_Texture * texture)
 {
@@ -1704,6 +1716,7 @@ D3D_CreateRenderer(SDL_Window * window, Uint32 flags)
     renderer->UpdateTextureYUV = D3D_UpdateTextureYUV;
     renderer->LockTexture = D3D_LockTexture;
     renderer->UnlockTexture = D3D_UnlockTexture;
+    renderer->SetTextureScaleMode = D3D_SetTextureScaleMode;
     renderer->SetRenderTarget = D3D_SetRenderTarget;
     renderer->QueueSetViewport = D3D_QueueSetViewport;
     renderer->QueueSetDrawColor = D3D_QueueSetViewport;  /* SetViewport and SetDrawColor are (currently) no-ops. */

src/render/direct3d11/SDL_render_d3d11.c

@@ -1523,6 +1523,18 @@ D3D11_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * texture)
     SAFE_RELEASE(textureData->stagingTexture);
 }
 
+static void
+D3D11_SetTextureScaleMode(SDL_Renderer * renderer, SDL_Texture * texture, SDL_ScaleMode scaleMode)
+{
+    D3D11_TextureData *textureData = (D3D11_TextureData *) texture->driverdata;
+    
+    if (!textureData) {
+        return;
+    }
+
+    textureData->scaleMode = (scaleMode == SDL_ScaleModeNearest) ?  D3D11_FILTER_MIN_MAG_MIP_POINT : D3D11_FILTER_MIN_MAG_MIP_LINEAR;
+}
+
 static int
 D3D11_SetRenderTarget(SDL_Renderer * renderer, SDL_Texture * texture)
 {
@@ -2498,6 +2510,7 @@ D3D11_CreateRenderer(SDL_Window * window, Uint32 flags)
     renderer->UpdateTextureYUV = D3D11_UpdateTextureYUV;
     renderer->LockTexture = D3D11_LockTexture;
     renderer->UnlockTexture = D3D11_UnlockTexture;
+    renderer->SetTextureScaleMode = D3D11_SetTextureScaleMode;
     renderer->SetRenderTarget = D3D11_SetRenderTarget;
     renderer->QueueSetViewport = D3D11_QueueSetViewport;
     renderer->QueueSetDrawColor = D3D11_QueueSetViewport;  /* SetViewport and SetDrawColor are (currently) no-ops. */

src/render/metal/SDL_render_metal.m

@@ -946,6 +946,18 @@ METAL_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * texture)
     texturedata.hasdata = YES;
 }}
 
+static void
+METAL_SetTextureScaleMode(SDL_Renderer * renderer, SDL_Texture * texture, SDL_ScaleMode scaleMode)
+{ @autoreleasepool {
+    METAL_TextureData *texturedata = (__bridge METAL_TextureData *)texture->driverdata;
+
+    if (scaleMode == SDL_ScaleModeNearest) {
+        texturedata.mtlsampler = data.mtlsamplernearest;
+    } else {
+        texturedata.mtlsampler = data.mtlsamplerlinear;
+    }
+}}
+
 static int
 METAL_SetRenderTarget(SDL_Renderer * renderer, SDL_Texture * texture)
 { @autoreleasepool {
@@ -1763,6 +1775,7 @@ METAL_CreateRenderer(SDL_Window * window, Uint32 flags)
     renderer->UpdateTextureYUV = METAL_UpdateTextureYUV;
     renderer->LockTexture = METAL_LockTexture;
     renderer->UnlockTexture = METAL_UnlockTexture;
+    renderer->SetTextureScaleMode = METAL_SetTextureScaleMode;
     renderer->SetRenderTarget = METAL_SetRenderTarget;
     renderer->QueueSetViewport = METAL_QueueSetViewport;
     renderer->QueueSetDrawColor = METAL_QueueSetDrawColor;

src/render/opengl/SDL_render_gl.c

@@ -768,6 +768,43 @@ GL_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * texture)
     GL_UpdateTexture(renderer, texture, rect, pixels, data->pitch);
 }
 
+static void
+GL_SetTextureScaleMode(SDL_Renderer * renderer, SDL_Texture * texture, SDL_ScaleMode scaleMode)
+{
+    GL_RenderData *renderdata = (GL_RenderData *) renderer->driverdata;
+    const GLenum textype = renderdata->textype;
+    GL_TextureData *data = (GL_TextureData *) texture->driverdata;
+    GLenum glScaleMode = (scaleMode == SDL_ScaleModeNearest) ? GL_NEAREST : GL_LINEAR;
+
+    renderdata->glEnable(textype);
+    renderdata->glBindTexture(textype, data->texture);
+    renderdata->glTexParameteri(textype, GL_TEXTURE_MIN_FILTER, glScaleMode);
+    renderdata->glTexParameteri(textype, GL_TEXTURE_MAG_FILTER, glScaleMode);
+    renderdata->glDisable(textype);
+
+    if (texture->format == SDL_PIXELFORMAT_YV12 ||
+        texture->format == SDL_PIXELFORMAT_IYUV) {
+        renderdata->glEnable(textype);
+        renderdata->glBindTexture(textype, data->utexture);
+        renderdata->glTexParameteri(textype, GL_TEXTURE_MIN_FILTER, glScaleMode);
+        renderdata->glTexParameteri(textype, GL_TEXTURE_MAG_FILTER, glScaleMode);
+
+        renderdata->glBindTexture(textype, data->vtexture);
+        renderdata->glTexParameteri(textype, GL_TEXTURE_MIN_FILTER, glScaleMode);
+        renderdata->glTexParameteri(textype, GL_TEXTURE_MAG_FILTER, glScaleMode);
+        renderdata->glDisable(textype);
+    }
+
+    if (texture->format == SDL_PIXELFORMAT_NV12 ||
+        texture->format == SDL_PIXELFORMAT_NV21) {
+        renderdata->glEnable(textype);
+        renderdata->glBindTexture(textype, data->utexture);
+        renderdata->glTexParameteri(textype, GL_TEXTURE_MIN_FILTER, glScaleMode);
+        renderdata->glTexParameteri(textype, GL_TEXTURE_MAG_FILTER, glScaleMode);
+        renderdata->glDisable(textype);
+    }
+}
+
 static int
 GL_SetRenderTarget(SDL_Renderer * renderer, SDL_Texture * texture)
 {
@@ -1577,6 +1614,7 @@ GL_CreateRenderer(SDL_Window * window, Uint32 flags)
     renderer->UpdateTextureYUV = GL_UpdateTextureYUV;
     renderer->LockTexture = GL_LockTexture;
     renderer->UnlockTexture = GL_UnlockTexture;
+    renderer->SetTextureScaleMode = GL_SetTextureScaleMode;
     renderer->SetRenderTarget = GL_SetRenderTarget;
     renderer->QueueSetViewport = GL_QueueSetViewport;
     renderer->QueueSetDrawColor = GL_QueueSetViewport;  /* SetViewport and SetDrawColor are (currently) no-ops. */

src/render/opengles/SDL_render_gles.c

@@ -492,6 +492,19 @@ GLES_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * texture)
     GLES_UpdateTexture(renderer, texture, &rect, data->pixels, data->pitch);
 }
 
+static void
+GLES_SetTextureScaleMode(SDL_Renderer * renderer, SDL_Texture * texture, SDL_ScaleMode scaleMode)
+{
+    GLES_RenderData *renderdata = (GLES_RenderData *) renderer->driverdata;
+    const GLenum textype = renderdata->textype;
+    GLES_TextureData *data = (GLES_TextureData *) texture->driverdata;
+    GLenum glScaleMode = (scaleMode == SDL_ScaleModeNearest) ? GL_NEAREST : GL_LINEAR;
+
+    renderdata->glBindTexture(data->type, data->texture);
+    renderdata->glTexParameteri(data->type, GL_TEXTURE_MIN_FILTER, glScaleMode);
+    renderdata->glTexParameteri(data->type, GL_TEXTURE_MAG_FILTER, glScaleMode);
+}
+
 static int
 GLES_SetRenderTarget(SDL_Renderer * renderer, SDL_Texture * texture)
 {
@@ -1141,6 +1154,7 @@ GLES_CreateRenderer(SDL_Window * window, Uint32 flags)
     renderer->UpdateTexture = GLES_UpdateTexture;
     renderer->LockTexture = GLES_LockTexture;
     renderer->UnlockTexture = GLES_UnlockTexture;
+    renderer->SetTextureScaleMode = GLES_SetTextureScaleMode;
     renderer->SetRenderTarget = GLES_SetRenderTarget;
     renderer->QueueSetViewport = GLES_QueueSetViewport;
     renderer->QueueSetDrawColor = GLES_QueueSetViewport;  /* SetViewport and SetDrawColor are (currently) no-ops. */

src/render/opengles2/SDL_render_gles2.c

@@ -1743,6 +1743,36 @@ GLES2_UnlockTexture(SDL_Renderer *renderer, SDL_Texture *texture)
     GLES2_UpdateTexture(renderer, texture, &rect, tdata->pixel_data, tdata->pitch);
 }
 
+static void
+GLES2_SetTextureScaleMode(SDL_Renderer * renderer, SDL_Texture * texture, SDL_ScaleMode scaleMode)
+{
+    GLES2_RenderData *renderdata = (GLES2_RenderData *) renderer->driverdata;
+    GLES2_TextureData *data = (GLES2_TextureData *) texture->driverdata;
+    GLenum glScaleMode = (scaleMode == SDL_ScaleModeNearest) ? GL_NEAREST : GL_LINEAR;
+
+    if (data->yuv) {
+        renderdata->glActiveTexture(GL_TEXTURE2);
+        renderdata->glBindTexture(data->texture_type, data->texture_v);
+        renderdata->glTexParameteri(data->texture_type, GL_TEXTURE_MIN_FILTER, glScaleMode);
+        renderdata->glTexParameteri(data->texture_type, GL_TEXTURE_MAG_FILTER, glScaleMode);
+
+        renderdata->glActiveTexture(GL_TEXTURE1);
+        renderdata->glBindTexture(data->texture_type, data->texture_u);
+        renderdata->glTexParameteri(data->texture_type, GL_TEXTURE_MIN_FILTER, glScaleMode);
+        renderdata->glTexParameteri(data->texture_type, GL_TEXTURE_MAG_FILTER, glScaleMode);
+    } else if (data->nv12) {
+        renderdata->glActiveTexture(GL_TEXTURE1);
+        renderdata->glBindTexture(data->texture_type, data->texture_u);
+        renderdata->glTexParameteri(data->texture_type, GL_TEXTURE_MIN_FILTER, glScaleMode);
+        renderdata->glTexParameteri(data->texture_type, GL_TEXTURE_MAG_FILTER, glScaleMode);
+    }
+
+    renderdata->glActiveTexture(GL_TEXTURE0);
+    renderdata->glBindTexture(data->texture_type, data->texture);
+    renderdata->glTexParameteri(data->texture_type, GL_TEXTURE_MIN_FILTER, glScaleMode);
+    renderdata->glTexParameteri(data->texture_type, GL_TEXTURE_MAG_FILTER, glScaleMode);
+}
+
 static int
 GLES2_SetRenderTarget(SDL_Renderer * renderer, SDL_Texture * texture)
 {
@@ -2064,6 +2094,7 @@ GLES2_CreateRenderer(SDL_Window *window, Uint32 flags)
     renderer->UpdateTextureYUV    = GLES2_UpdateTextureYUV;
     renderer->LockTexture         = GLES2_LockTexture;
     renderer->UnlockTexture       = GLES2_UnlockTexture;
+    renderer->SetTextureScaleMode = GLES2_SetTextureScaleMode;
     renderer->SetRenderTarget     = GLES2_SetRenderTarget;
     renderer->QueueSetViewport    = GLES2_QueueSetViewport;
     renderer->QueueSetDrawColor   = GLES2_QueueSetViewport;  /* SetViewport and SetDrawColor are (currently) no-ops. */

src/render/psp/SDL_render_psp.c

@@ -428,6 +428,12 @@ PSP_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * texture)
     PSP_UpdateTexture(renderer, texture, &rect, psp_texture->data, psp_texture->pitch);
 }
 
+static void
+PSP_SetTextureScaleMode(SDL_Renderer * renderer, SDL_Texture * texture, SDL_ScaleMode scaleMode)
+{
+    /* Nothing to do because TextureActivate takes care of it */
+}
+
 static int
 PSP_SetRenderTarget(SDL_Renderer * renderer, SDL_Texture * texture)
 {
@@ -938,6 +944,7 @@ PSP_CreateRenderer(SDL_Window * window, Uint32 flags)
     renderer->UpdateTexture = PSP_UpdateTexture;
     renderer->LockTexture = PSP_LockTexture;
     renderer->UnlockTexture = PSP_UnlockTexture;
+    renderer->SetTextureScaleMode = PSP_SetTextureScaleMode;
     renderer->SetRenderTarget = PSP_SetRenderTarget;
     renderer->QueueSetViewport = PSP_QueueSetViewport;
     renderer->QueueSetDrawColor = PSP_QueueSetViewport;  /* SetViewport and SetDrawColor are (currently) no-ops. */

src/render/software/SDL_render_sw.c

@@ -179,6 +179,11 @@ SW_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * texture)
 {
 }
 
+static void
+SW_SetTextureScaleMode(SDL_Renderer * renderer, SDL_Texture * texture, SDL_ScaleMode scaleMode)
+{
+}
+
 static int
 SW_SetRenderTarget(SDL_Renderer * renderer, SDL_Texture * texture)
 {
@@ -830,6 +835,7 @@ SW_CreateRendererForSurface(SDL_Surface * surface)
     renderer->UpdateTexture = SW_UpdateTexture;
     renderer->LockTexture = SW_LockTexture;
     renderer->UnlockTexture = SW_UnlockTexture;
+    renderer->SetTextureScaleMode = SW_SetTextureScaleMode;
     renderer->SetRenderTarget = SW_SetRenderTarget;
     renderer->QueueSetViewport = SW_QueueSetViewport;
     renderer->QueueSetDrawColor = SW_QueueSetViewport;  /* SetViewport and SetDrawColor are (currently) no-ops. */

src/video/directfb/SDL_DirectFB_render.c

@@ -550,6 +550,11 @@ DirectFB_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * texture)
     }
 }
 
+static void
+DirectFB_SetTextureScaleMode()
+{
+}
+
 #if 0
 static void
 DirectFB_DirtyTexture(SDL_Renderer * renderer, SDL_Texture * texture,
@@ -966,6 +971,7 @@ DirectFB_CreateRenderer(SDL_Window * window, Uint32 flags)
     renderer->UpdateTexture = DirectFB_UpdateTexture;
     renderer->LockTexture = DirectFB_LockTexture;
     renderer->UnlockTexture = DirectFB_UnlockTexture;
+    renderer->SetTextureScaleMode = DirectFB_SetTextureScaleMode;
     renderer->QueueSetViewport = DirectFB_QueueSetViewport;
     renderer->QueueSetDrawColor = DirectFB_QueueSetViewport;  /* SetViewport and SetDrawColor are (currently) no-ops. */
     renderer->QueueDrawPoints = DirectFB_QueueDrawPoints;