SDL Wiki

SDL_GLattr

An enumeration of OpenGL configuration attributes.

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)

Code Examples

SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
SDL_GL_CreateContext(window);

Remarks

While you can set most OpenGL attributes normally, the attributes listed above must be known before SDL creates the window that will be used with the OpenGL context. These attributes are set and read with SDL_GL_SetAttribute() and SDL_GL_GetAttribute().

In some cases, these attributes are minimum requests; the GL does not promise to give you exactly what you asked for. It's possible to ask for a 16-bit depth buffer and get a 24-bit one instead, for example, or to ask for no stencil buffer and still have one available. Context creation should fail if the GL can't provide your requested attributes at a minimum, but you should check to see exactly what you got.

Multisample anti-aliasing is a type of full screen anti-aliasing. Multipsampling defaults to off but can be turned on by setting SDL_GL_MULTISAMPLEBUFFERS to 1 and SDL_GL_MULTISAMPLESAMPLES to a value greater than 0. Typical values are 2 and 4.

SDL_GL_CONTEXT_PROFILE_MASK determines the type of context created, while both SDL_GL_CONTEXT_MAJOR_VERSION and SDL_GL_CONTEXT_MINOR_VERSION determine which version. All three attributes must be set prior to creating the first window, and in general you can't change the value of SDL_GL_CONTEXT_PROFILE_MASK without first destroying all windows created with the previous setting.

SDL_GL_CONTEXT_RELEASE_BEHAVIOR can be set to SDL_GL_CONTEXT_RELEASE_BEHAVIOR_NONE or SDL_GL_CONTEXT_RELEASE_BEHAVIOR_FLUSH.

SDL_GL_CreateContext
SDL_GL_GetAttribute
SDL_GL_SetAttribute

CategoryEnum, CategoryVideo


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