Skip to content
Iris Docs

RENDERTARGETS

/* RENDERTARGETS: X,Y,Z */

Location: any fragment stage (.fsh) of any program

This directive is used to configure which color attachments a fragment program outputs to. Replace X,Y,Z with the comma separated list of indices of color attachments. For example, putting /* RENDERTARGETS: 0,3,7,13 */ in composite.fsh would configure that program to write to colortex0, colortex3, colortex7, and colortex13. The comment can be placed anywhere in the .fsh file. If the directive (or the DRAWBUFFERS directive) is not found in the file, the first 8 buffers will be bound in order.

Note: This directive must include the multi-line comments and should be on its own line.

The directive creates a map between the color attachment index used in the glsl code and the colortex or shadowcolor buffer. For example, if the line /* RENDERTARGETS: 0,3,7,13 */ is used, colortex0 would be at index 0 and colortex13 at index 3. There are three methods to access this output depending on the glsl version in use:

  1. Legacy versions and compatibility profiles have access to gl_FragData[<index>], an array that can be written to with the attachment index like a standard vec4 array. In the above example writing to gl_FragData[2] would write to colortex7.
  2. Modern versions (130+) can use the out vec4 outColorN; variable, where N is replaced with the array index. In the above example writing to outColor2 would write to colortex7.
  3. Newer modern versions (330+) can use layout qualifiers to specify the index, allowing the varible name to be changed. In the above example layout(location = 2) out vec4 anArbitraryOutputName; would write to colortex7.