16 bits float + MSAA on x1800

OpenGL OpenGL: Advanced Coding
1

Is it possible to create a 16 bits float renderable surface with MSAA enabled?

I can create a 16 bits float surface without MSAA with this parameter:

int attr[] =
{
	WGL_PIXEL_TYPE_ARB, WGL_TYPE_RGBA_FLOAT_ATI,
	WGL_SUPPORT_OPENGL_ARB,	TRUE,
	WGL_DRAW_TO_PBUFFER_ARB,	TRUE,
	WGL_RED_BITS_ARB,	16,
	WGL_GREEN_BITS_ARB,	16,
	WGL_BLUE_BITS_ARB,	16,
	WGL_ALPHA_BITS_ARB,	16,
	WGL_DEPTH_BITS_ARB,	24,
	WGL_DOUBLE_BUFFER_ARB,	FALSE,
	0
};

I can create a 8 bits surface with MSAA with this parameter:

int attr[] =
{
	WGL_SUPPORT_OPENGL_ARB,	TRUE,
	WGL_DRAW_TO_PBUFFER_ARB,	TRUE,
	WGL_RED_BITS_ARB,	8,
	WGL_GREEN_BITS_ARB,	8,
	WGL_BLUE_BITS_ARB,	8,
	WGL_ALPHA_BITS_ARB,	8,
	WGL_DEPTH_BITS_ARB,	24,
	WGL_DOUBLE_BUFFER_ARB,	FALSE,
	WGL_SAMPLE_BUFFERS_ARB, GL_TRUE,
	WGL_SAMPLES_ARB, 6,
	0
};

But when I use this parameter to create a 16 bits float surface with MSAA, wglChoosePixelFormatARB return a count of 0.

int attr[] =
{
	WGL_PIXEL_TYPE_ARB, WGL_TYPE_RGBA_FLOAT_ATI,
	WGL_SUPPORT_OPENGL_ARB,	TRUE,
	WGL_DRAW_TO_PBUFFER_ARB,	TRUE,
	WGL_RED_BITS_ARB,	16,
	WGL_GREEN_BITS_ARB,	16,
	WGL_BLUE_BITS_ARB,	16,
	WGL_ALPHA_BITS_ARB,	16,
	WGL_DEPTH_BITS_ARB,	24,
	WGL_DOUBLE_BUFFER_ARB,	FALSE,
	WGL_SAMPLE_BUFFERS_ARB, GL_TRUE,
	WGL_SAMPLES_ARB, 6,
	0
};

Im using the Catalyst 5.11.

2

FP16 MSAA is unfortunately not yet supported in OpenGL.

3

do you know if it, any other X1K features, are in the pipeline as yet, or is a ‘wait a few months and ask again’ situation?

4

Do you know if the FireGL driver is usually quicker to integrate new features like this one (compared to the Catalyst driver) ?

Ozo.

5

Thank you for your answer Humus.

6

I wonder if the blending performance issues I have are related to this. I’m using a 16-bit floating point ABGR pbuffer on my X1800 with 5.12 drivers under Windows. Performance is fine until I enable GL_BLEND in the pbuffer context, it seems blending is done in software then. According to the “Radeon X1x00 Programming Guide” from the ATI SDK blending should be supported in hardware for A16B16G16R16F textures.

@Humus: Does this only apply to DirectX currently, so is the OpenGL driver lacking features?

7

I have the same blending problem with my test app. Maybe the X1800 functionalities are not yet implemented in the OpenGL driver?