diff --git a/src/gl/renderer/gl_postprocess.cpp b/src/gl/renderer/gl_postprocess.cpp
index 9edd43c2a..d327e9eb3 100644
--- a/src/gl/renderer/gl_postprocess.cpp
+++ b/src/gl/renderer/gl_postprocess.cpp
@@ -236,11 +236,11 @@ void FGLRenderer::DrawPresentTexture(const IntRect &box, bool applyGamma)
 		// Full screen exclusive mode treats a rgba16f frame buffer as linear.
 		// It probably will eventually in desktop mode too, but the DWM doesn't seem to support that.
 		mPresentShader->Uniforms->InvGamma *= 2.2f;
-		mPresentShader->Uniforms->ColorScale = (gl_dither_bpc == -1) ? 1023.0f : (float)(1 << gl_dither_bpc - 1);
+		mPresentShader->Uniforms->ColorScale = (gl_dither_bpc == -1) ? 1023.0f : (float)((1 << gl_dither_bpc) - 1);
 	}
 	else
 	{
-		mPresentShader->Uniforms->ColorScale = (gl_dither_bpc == -1) ? 255.0f : (float)(1 << gl_dither_bpc - 1);
+		mPresentShader->Uniforms->ColorScale = (gl_dither_bpc == -1) ? 255.0f : (float)((1 << gl_dither_bpc) - 1);
 	}
 	mPresentShader->Uniforms->Scale = { screen->mScreenViewport.width / (float)mBuffers->GetWidth(), screen->mScreenViewport.height / (float)mBuffers->GetHeight() };
 	mPresentShader->Uniforms.Set();
diff --git a/src/gl/renderer/gl_stereo3d.cpp b/src/gl/renderer/gl_stereo3d.cpp
index 829dbb1f1..2684622d8 100644
--- a/src/gl/renderer/gl_stereo3d.cpp
+++ b/src/gl/renderer/gl_stereo3d.cpp
@@ -163,7 +163,7 @@ static void prepareInterleavedPresent(FPresentShaderBase& shader)
 		shader.Uniforms->Saturation = clamp<float>(vid_saturation, -15.0f, 15.0f);
 		shader.Uniforms->GrayFormula = static_cast<int>(gl_satformula);
 	}
-	shader.Uniforms->ColorScale = (gl_dither_bpc == -1) ? 255.0f : (float)(1 << gl_dither_bpc - 1);
+	shader.Uniforms->ColorScale = (gl_dither_bpc == -1) ? 255.0f : (float)((1 << gl_dither_bpc) - 1);
 	shader.Uniforms->Scale = {
 		screen->mScreenViewport.width / (float)GLRenderer->mBuffers->GetWidth(),
 		screen->mScreenViewport.height / (float)GLRenderer->mBuffers->GetHeight()