Unit CastleGLCubeMaps

Classes, Interfaces, Objects and Records
Constants
Variables

Description

OpenGL utilities for cube (environment) maps.

Uses

Overview

Functions and Procedures

procedure SHVectorGLCapture( var SHVector: array of Single; const CapturePoint: TVector3; const Render: TCubeMapRenderSimpleFunction; const MapScreenX, MapScreenY: Integer; const ScaleColor: Single); experimental;
procedure GLCaptureCubeMapImages( const Images: TCubeMapImages; const CapturePoint: TVector3; const Render: TRenderFromViewFunction; const ProjectionNear, ProjectionFar: Single);
function GLCaptureCubeMapComposite( const Size: Cardinal; const CapturePoint: TVector3; const Render: TRenderFromViewFunction; const ProjectionNear, ProjectionFar: Single): TCompositeImage;
procedure GLCaptureCubeMapTexture( const Tex: TGLuint; const Size: Cardinal; const CapturePoint: TVector3; const Render: TRenderFromViewFunction; const ProjectionNear, ProjectionFar: Single; RenderToTexture: TGLRenderToTexture);

Types

TCubeMapRenderSimpleFunction = procedure (ForCubeMap: boolean); experimental;

Description

Functions and Procedures

procedure SHVectorGLCapture( var SHVector: array of Single; const CapturePoint: TVector3; const Render: TCubeMapRenderSimpleFunction; const MapScreenX, MapScreenY: Integer; const ScaleColor: Single); experimental;

Warning: this symbol is experimental.

Calculate spherical harmonics basis describing environment rendered by OpenGL. Environment is rendered by Render(true) callback, from the CapturePoint. It's rendered to color buffer, and captured as grayscale. Captured pixel value is just assumed to be the value of spherical function at this direction. It's also scaled by ScaleColor (since rendering to OpenGL catches values in 0..1 range, but SH vector can express values from any range).

This changes RenderContext.Viewport, so be sure to reset RenderContext.Viewport to something normal after calling this.

The maps will be drawn in the color buffer (from positions MapScreenX, Y), so will actually be visible (call this before RenderContext.Clear or such if you want to hide them).

procedure GLCaptureCubeMapImages( const Images: TCubeMapImages; const CapturePoint: TVector3; const Render: TRenderFromViewFunction; const ProjectionNear, ProjectionFar: Single);

Capture cube map by rendering environment from CapturePoint.

Environment is rendered by the Render callback. It will be called with custom TRenderingCamera instance, with TRenderingCamera.Target set to rtCubeMapEnvironment, and matrix set to appropriate view from the CapturePoint.

Cube map is recorded in six images you provide in the Images parameter. These must be already created TCastleImage instances, with the exact same size. (They do not have to be square, or have power-of-two size, or honor GL_MAX_CUBE_MAP_TEXTURE_SIZE_ARB limit, as we do not initialize actual OpenGL cube map here. You can use generated images for any purpose.) The classes of these images will also matter — e.g. use TGrayscaleImage to capture scene as grayscale, use TRGBImage for RGB colors.

This changes RenderContext.Viewport, so be sure to reset RenderContext.Viewport to something normal after calling this.

ProjectionNear, ProjectionFar parameters will be used to set GL projection matrix. ProjectionFar may be equal to ZFarInfinity, as always.

function GLCaptureCubeMapComposite( const Size: Cardinal; const CapturePoint: TVector3; const Render: TRenderFromViewFunction; const ProjectionNear, ProjectionFar: Single): TCompositeImage;

Capture cube map to composite (DDS, KTX...) image by rendering environment from CapturePoint.

See GLCaptureCubeMapImages for documentation, this works the same, but it creates TCompositeImage instance containing all six images.

procedure GLCaptureCubeMapTexture( const Tex: TGLuint; const Size: Cardinal; const CapturePoint: TVector3; const Render: TRenderFromViewFunction; const ProjectionNear, ProjectionFar: Single; RenderToTexture: TGLRenderToTexture);

Capture cube map to OpenGL cube map texture by rendering environment from CapturePoint.

See GLCaptureCubeMapImages for documentation, this works the same, but it captures images to given OpenGL texture name Tex. Tex must already be created cube map texture (with OpenGL size and internal formats set), with square images of Size. This also means that Size must be a valid OpenGL cube map texture size, you can check it by IsCubeMapTextureSized.

This captures the cube map images to "zero" texture level. If you use mipmaps, it's your problem how to generate other texture levels — in the simplest case, call GenerateMipmap(GL_TEXTURE_CUBE_MAP).

It uses RenderToTexture to render to the texture, so it will use framebuffer if available, and it's fast.

Types

TCubeMapRenderSimpleFunction = procedure (ForCubeMap: boolean); experimental;

Warning: this symbol is experimental.

 

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