diff --git a/src/gl/renderer/gl_renderstate.cpp b/src/gl/renderer/gl_renderstate.cpp
index 917170872..6f5b9be14 100644
--- a/src/gl/renderer/gl_renderstate.cpp
+++ b/src/gl/renderer/gl_renderstate.cpp
@@ -136,7 +136,7 @@ bool FRenderState::ApplyShader()
 		}
 	}
 
-	glColor4fv(mColor.vec);
+	glVertexAttrib4fv(VATTR_COLOR, mColor.vec);
 
 	activeShader->muDesaturation.Set(mDesaturation / 255.f);
 	activeShader->muFogEnabled.Set(fogset);
diff --git a/src/gl/scene/gl_skydome.cpp b/src/gl/scene/gl_skydome.cpp
index 240bf6762..c54fb8c16 100644
--- a/src/gl/scene/gl_skydome.cpp
+++ b/src/gl/scene/gl_skydome.cpp
@@ -82,10 +82,10 @@ FSkyVertexBuffer::FSkyVertexBuffer()
 	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 	glVertexPointer(3, GL_FLOAT, sizeof(FSkyVertex), &VSO->x);
 	glTexCoordPointer(2, GL_FLOAT, sizeof(FSkyVertex), &VSO->u);
-	glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(FSkyVertex), &VSO->color);
+	glVertexAttribPointer(VATTR_COLOR, 4, GL_UNSIGNED_BYTE, true, sizeof(FSkyVertex), &VSO->color);
 	glEnableClientState(GL_VERTEX_ARRAY);
 	glEnableClientState(GL_TEXTURE_COORD_ARRAY);
-	glEnableClientState(GL_COLOR_ARRAY);
+	glEnableVertexAttribArray(VATTR_COLOR);
 	glBindVertexArray(0);
 
 }
diff --git a/src/gl/shaders/gl_shader.cpp b/src/gl/shaders/gl_shader.cpp
index 4373955c2..ba3db27ea 100644
--- a/src/gl/shaders/gl_shader.cpp
+++ b/src/gl/shaders/gl_shader.cpp
@@ -120,6 +120,7 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 				fp_comb.Substitute("vec4 frag = ProcessTexel();", "vec4 frag = Process(vec4(1.0));");
 			}
 			fp_comb << pp_data.GetString().GetChars();
+			fp_comb.Substitute("gl_TexCoord[0]", "vTexCoord");	// fix old custom shaders.
 
 			if (pp_data.GetString().IndexOf("ProcessLight") < 0)
 			{
@@ -156,6 +157,8 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 
 	glAttachShader(hShader, hVertProg);
 	glAttachShader(hShader, hFragProg);
+	glBindAttribLocation(hShader, VATTR_COLOR, "aColor");
+	glBindAttribLocation(hShader, VATTR_VERTEX2, "aVertex2");
 
 	glLinkProgram(hShader);
 
@@ -213,8 +216,6 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 	modelmatrix_index = glGetUniformLocation(hShader, "ModelMatrix");
 	texturematrix_index = glGetUniformLocation(hShader, "TextureMatrix");
 
-	glBindAttribLocation(hShader, VATTR_VERTEX2, "aVertex2");
-
 	glUseProgram(hShader);
 
 	int texture_index = glGetUniformLocation(hShader, "texture2");
diff --git a/src/gl/shaders/gl_shader.h b/src/gl/shaders/gl_shader.h
index bed37cbb0..2e0731346 100644
--- a/src/gl/shaders/gl_shader.h
+++ b/src/gl/shaders/gl_shader.h
@@ -9,6 +9,7 @@ extern bool gl_shaderactive;
 
 enum
 {
+	VATTR_COLOR = 14,
 	VATTR_VERTEX2 = 15
 };
 
diff --git a/wadsrc/static/shaders/glsl/main.vp b/wadsrc/static/shaders/glsl/main.vp
index e1349857e..8a1709ecf 100644
--- a/wadsrc/static/shaders/glsl/main.vp
+++ b/wadsrc/static/shaders/glsl/main.vp
@@ -1,4 +1,5 @@
 
+in vec4 aColor;
 #ifndef SIMPLE	// we do not need these for simple shaders
 in vec4 aVertex2;
 out vec4 pixelpos;
@@ -43,7 +44,7 @@ void main()
 
 	vec4 eyeCoordPos = ViewMatrix * worldcoord;
 
-	vColor = gl_Color;
+	vColor = aColor;
 
 	#ifndef SIMPLE
 		pixelpos.xyz = worldcoord.xyz;