Opengl float buffer

I'm writing my first ray tracer. I want to make it work in开发者_如何学运维 real-time. I want to use opengl for display. I want to write my screen to floating point buffer and display the buffer. What extension and/or buffer type I need?

Thanks in advance!

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I'm writing my first ray tracer. I want to make it work in real-time.

Ambitious!

I want to use opengl for display. I want to write my screen to floating point buffer and display the buffer.

OpenGL can read from float buffers directly, e.g.

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_FLOAT, data);

But OpenGL may choose any internal format that matches your selection. GL_RGB internal format can be anything that can somehow store RGB data. You can be specific about what you want. For example GL_RGB16 tells OpenGL you want 16 bits resolution per channel. The implementation may choose to use 24 bits per channel, as this allows for 16 bit to be stored. But ultimately the implementation decides, which internal format it will be, based on the constraints you put upon it.

Floating point framebuffers and textures are supported in OpenGL through extensions GL_ARB_texture_float, GLX_ARB_fbconfig_float, WGL_ARB_fbconfig_float, but due to patent issues not all OpenGL implementations implement it (ATI and NVidia do).