unoplatform/uno · error · Exception

Program link failed: {infoLog}

Error message

Program link failed: {infoLog}

What it means

CreateProgram in IntegerTexturesGlCanvasElement links the integer-texture sample's shaders and throws the info log on link failure. Because the fragment shader writes to integer render targets (`layout(location=0) out uvec4`), link failures often come from integer-output or integer-sampler interface mismatches.

Source

Thrown at src/SamplesApp/SamplesApp.Samples/Windows_UI_Composition/IntegerTexturesGlCanvasElement.cs:251

			gl.BindVertexArray(_quadVao);
			gl.DrawArrays(PrimitiveType.Triangles, 0, 6);
			gl.ActiveTexture(TextureUnit.Texture0);

			Invalidate();
		}

		private static uint CreateProgram(GL gl, string vertexSource, string fragmentSource)
		{
			var vs = CompileShader(gl, ShaderType.VertexShader, vertexSource);
			var fs = CompileShader(gl, ShaderType.FragmentShader, fragmentSource);
			var prog = gl.CreateProgram();
			gl.AttachShader(prog, vs);
			gl.AttachShader(prog, fs);
			gl.LinkProgram(prog);
			gl.GetProgram(prog, ProgramPropertyARB.LinkStatus, out int linkStatus);
			if (linkStatus != (int)GLEnum.True)
			{
				throw new Exception("Program link failed: " + gl.GetProgramInfoLog(prog));
			}
			gl.DetachShader(prog, vs);
			gl.DetachShader(prog, fs);
			gl.DeleteShader(vs);
			gl.DeleteShader(fs);
			return prog;
		}

		private static uint CompileShader(GL gl, ShaderType type, string source)
		{
			var sh = gl.CreateShader(type);
			gl.ShaderSource(sh, source);
			gl.CompileShader(sh);
			gl.GetShader(sh, ShaderParameterName.CompileStatus, out int status);
			if (status != (int)GLEnum.True)
			{
				throw new Exception($"{type} compile failed: " + gl.GetShaderInfoLog(sh));
			}

View on GitHub (pinned to 0418340488)

Solutions

1. Read the info log for the offending output/sampler.
2. Match fragment output types to the framebuffer's integer color attachment types.
3. Use usampler2D/isampler2D only with integer-format textures, and sampler2D only with normalized formats.
4. Target #version 300 es / GL 330+ for integer fragment outputs.

Example fix

// before — integer output to a float FBO, or float sampler on integer tex
out vec4 fragColor;          // mismatched with RGBA32UI attachment
uniform sampler2D uTex;       // mismatched with RGBA32UI texture

// after
layout(location=0) out uvec4 fragColor;
uniform usampler2D uTex;

// Ensure fragment output types match the integer framebuffer attachment
if (!fragmentSource.Contains("uvec4") && !fragmentSource.Contains("ivec4"))
    throw new InvalidOperationException("Integer FBO requires integer fragment outputs (uvec4/ivec4).");

try { return CreateProgram(gl, vert, frag); }
catch (Exception ex) { Log.Error($"IntegerTextures link failed: {ex.Message}"); throw; }

When it happens

Trigger: Fragment output declared `uvec4`/`ivec4` but the framebuffer attachment is a float texture (or vice-versa); usampler2D declared but the bound texture isn't integer format; varying mismatch between stages; #version too low for integer fragment outputs.

Common situations: Mixing integer fragment outputs with a non-integer FBO; ES2/WebGL1 context lacking integer render targets; sampler type (sampler2D vs usampler2D) not matching the texture's internal format.

Related errors

• {type} compile failed: {infoLog}
• Program link failed: {infoLog}
• Program link failed: {infoLog}
• {type} compile failed: {infoLog}
• {type} compile failed: {infoLog}

AI-assisted analysis of unoplatform/uno@0418340488 (2026-08-13). Data as JSON: /api/errors/760d67e62f5a758c. Report an issue: GitHub.