Differences between revisions 7 and 8

SDL_GL_SetAttribute

Use this function to set an OpenGL window attribute before window creation.

Contents

SDL_GL_SetAttribute

Syntax

int SDL_GL_SetAttribute(SDL_GLattr attr,
                        int        value)

Function Parameters

attr	the SDL_GLattr to set; see Remarks for details
value	the desired value for the attribute

Return Value

Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.

Code Examples

SDL_Window *window;
SDL_GLContext context;

SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 5);
SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 5);
SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 5);
SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);

window = SDL_CreateWindow("OpenGL Window", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 480, SDL_WINDOW_OPENGL);
if (!window) {
    fprintf(stderr, "Couldn't create window: %s\n", SDL_GetError());
    return;
}

context = SDL_GL_CreateContext(window);
if (!context) {
    fprintf(stderr, "Couldn't create context: %s\n", SDL_GetError());
    return;
}

printf("Red size: %d, Green size: %d, Blue size: %d\n",
    SDL_GL_GetAttribute(SDL_GL_RED_SIZE),
    SDL_GL_GetAttribute(SDL_GL_GREEN_SIZE),
    SDL_GL_GetAttribute(SDL_GL_BLUE_SIZE));

Remarks

This function sets the OpenGL attribute attr to value. The requested attributes should be set before creating an OpenGL window. You should use SDL_GL_GetAttribute() to check the values after creating the OpenGL context, since the values obtained can differ from the requested ones.

attr can be one of these values:

SDL_GL_RED_SIZE	the minimum number of bits for the red channel of the color buffer; defaults to 3
SDL_GL_GREEN_SIZE	the minimum number of bits for the green channel of the color buffer; defaults to 3
SDL_GL_BLUE_SIZE	the minimum number of bits for the blue channel of the color buffer; defaults to 2
SDL_GL_ALPHA_SIZE	the minimum number of bits for the alpha channel of the color buffer; defaults to 0
SDL_GL_BUFFER_SIZE	the minimum number of bits for frame buffer size; defaults to 0
SDL_GL_DOUBLEBUFFER	whether the output is single or double buffered; defaults to double buffering on
SDL_GL_DEPTH_SIZE	the minimum number of bits in the depth buffer; defaults to 16
SDL_GL_STENCIL_SIZE	the minimum number of bits in the stencil buffer; defaults to 0
SDL_GL_ACCUM_RED_SIZE	the minimum number of bits for the red channel of the accumulation buffer; defaults to 0
SDL_GL_ACCUM_GREEN_SIZE	the minimum number of bits for the green channel of the accumulation buffer; defaults to 0
SDL_GL_ACCUM_BLUE_SIZE	the minimum number of bits for the blue channel of the accumulation buffer; defaults to 0
SDL_GL_ACCUM_ALPHA_SIZE	the minimum number of bits for the alpha channel of the accumulation buffer; defaults to 0
SDL_GL_STEREO	whether the output is stereo 3D; defaults to off
SDL_GL_MULTISAMPLEBUFFERS	the number of buffers used for multisample anti-aliasing; defaults to 0; see Remarks for details
SDL_GL_MULTISAMPLESAMPLES	the number of samples used around the current pixel used for multisample anti-aliasing; defaults to 0; see Remarks for details
SDL_GL_ACCELERATED_VISUAL	set to 1 to require hardware acceleration, set to 0 to force software rendering; defaults to allow either
SDL_GL_RETAINED_BACKING	not used (deprecated)
SDL_GL_CONTEXT_MAJOR_VERSION	OpenGL context major version; see Remarks for details
SDL_GL_CONTEXT_MINOR_VERSION	OpenGL context minor version; see Remarks for details
SDL_GL_CONTEXT_FLAGS	some combination of 0 or more of elements of the SDL_GLcontextFlag enumeration; defaults to 0
SDL_GL_CONTEXT_PROFILE_MASK	type of GL context (Core, Compatibility, ES). See SDL_GLprofile; default value depends on platform
SDL_GL_SHARE_WITH_CURRENT_CONTEXT	OpenGL context sharing; defaults to 0
SDL_GL_FRAMEBUFFER_SRGB_CAPABLE	requests sRGB capable visual; defaults to 0 (>= SDL 2.0.1)
SDL_GL_CONTEXT_RELEASE_BEHAVIOR	sets context the release behavior; defaults to 1 (>= SDL 2.0.4)
SDL_GL_CONTEXT_EGL	not used (deprecated)

Related Functions

SDL_GL_GetAttribute

CategoryAPI, CategoryVideo

-  ⇤ ← Revision 7 as of 2010-08-30 00:15:45 → 
  Size: 1740
  Editor: SheenaSmith
  Comment: minor change
+   ← Revision 8 as of 2010-08-30 00:31:12 → ⇥
  Size: 2014
  Editor: Sam Lantinga
  Comment: Fixed code example for SDL 1.3
-Deletions are marked like this.
+Additions are marked like this.
 Line 3:
-||<tablewidth="100%" style="color: #FF0000;" :> DRAFT||
-Line 24:
+Line 23:
-*<<BR>>
-Line 26:
+Line 24:
-SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
if ( (screen=SDL_SetVideoMode( 640, 480, 16, SDL_OPENGL )) == NULL ) {
    fprintf(stderr, "Couldn't set GL mode: %s\n", SDL_GetError());
    SDL_Quit();
+SDL_Window *window;
SDL_GLContext context;

SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 5);
SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 5);
SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 5);
SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);

window = SDL_CreateWindow("OpenGL Window", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 480, SDL_WINDOW_OPENGL);
if (!window) {
    fprintf(stderr, "Couldn't create window: %s\n", SDL_GetError());
-Line 36:
+Line 38:
+context = SDL_GL_CreateContext(window);
if (!context) {
    fprintf(stderr, "Couldn't create context: %s\n", SDL_GetError());
    return;
}

printf("Red size: %d, Green size: %d, Blue size: %d\n",
    SDL_GL_GetAttribute(SDL_GL_RED_SIZE),
    SDL_GL_GetAttribute(SDL_GL_GREEN_SIZE),
    SDL_GL_GetAttribute(SDL_GL_BLUE_SIZE));
-Line 37:
+Line 50:
-<<BR>>*

<<Color2(green,The SDL_!SetVideoMode part of the example needs to be updated.)>>
-Line 42:
+Line 52:
-This function sets the OpenGL attribute '''attr''' to '''value'''. The requested attributes will take effect after creating an OpenGL context. You should use [[SDL_GL_GetAttribute]]() to check the values after creating the context, since the values obtained can differ from the requested ones.
+This function sets the OpenGL attribute '''attr''' to '''value'''. The requested attributes should be set before creating an OpenGL window. You should use [[SDL_GL_GetAttribute]]() to check the values after creating the OpenGL context, since the values obtained can differ from the requested ones.

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