diff --git a/source/glbackend/glbackend.cpp b/source/glbackend/glbackend.cpp
index 7201c5406..4b222a273 100644
--- a/source/glbackend/glbackend.cpp
+++ b/source/glbackend/glbackend.cpp
@@ -427,7 +427,7 @@ void GLInstance::SetBlendFunc(int src, int dst)
 	glBlendFunc(blendstyles[src], blendstyles[dst]);
 }
 
-static int renderops[] = { GL_FUNC_ADD, GL_FUNC_SUBTRACT, GL_FUNC_REVERSE_SUBTRACT };
+static int renderops[] = { GL_FUNC_ADD, GL_FUNC_ADD, GL_FUNC_SUBTRACT, GL_FUNC_REVERSE_SUBTRACT };
 
 void GLInstance::SetBlendOp(int op)
 {
diff --git a/source/glbackend/hw_draw2d.cpp b/source/glbackend/hw_draw2d.cpp
index 460466ffe..c9ec925d0 100644
--- a/source/glbackend/hw_draw2d.cpp
+++ b/source/glbackend/hw_draw2d.cpp
@@ -287,7 +287,7 @@ void fullscreen_tint_gl_blood(int tint_blood_r, int tint_blood_g, int tint_blood
 	vt[2].Set(.0f, -2.5f);
 	GLInterface.Draw(DT_TRIANGLES, data.first, 3);
 	GLInterface.SetBlendOp(STYLEOP_Add);
-	GLInterface.SetColorub(0, 0, 0, 0);
+	GLInterface.SetColorub(255, 255, 255, 255);
 	GLInterface.SetBlendFunc(STYLEALPHA_Src, STYLEALPHA_InvSrc);
 	GLInterface.UseColorOnly(false);
 
diff --git a/wadsrc/static/demolition/shaders/glsl/polymost.fpp b/wadsrc/static/demolition/shaders/glsl/polymost.fpp
deleted file mode 100644
index e9dba291b..000000000
--- a/wadsrc/static/demolition/shaders/glsl/polymost.fpp
+++ /dev/null
@@ -1,235 +0,0 @@
-#version 330
-
-const int RF_ColorOnly = 1;
-const int RF_UsePalette = 2;
-const int RF_DetailMapping = 4;
-const int RF_GlowMapping = 8;
-const int RF_Brightmapping = 16;
-const int RF_NPOTEmulation = 32;
-const int RF_ShadeInterpolate = 64;
-const int RF_FogDisabled = 128;
-
-const int RF_HICTINT_Grayscale = 0x10000;
-const int RF_HICTINT_Invert = 0x20000;
-const int RF_HICTINT_Colorize = 0x40000;
-const int RF_HICTINT_BLEND_Screen = 0x80000;
-const int RF_HICTINT_BLEND_Overlay = 0x100000;
-const int RF_HICTINT_BLEND_Hardlight = 0x200000;
-const int RF_HICTINT_BLENDMASK = RF_HICTINT_BLEND_Screen | RF_HICTINT_BLEND_Overlay | RF_HICTINT_BLEND_Hardlight;
-
-
-//s_texture points to an indexed color texture
-uniform sampler2D s_texture;
-//s_palswap is the palette swap texture where u is the color index and v is the shade
-uniform sampler2D s_palswap;
-//s_palette is the base palette texture where u is the color index
-uniform sampler2D s_palette;
-
-uniform sampler2D s_detail;
-uniform sampler2D s_glow;
-uniform sampler2D s_brightmap;
-
-uniform float u_shade;
-uniform float u_numShades;
-uniform float u_shadeDiv;
-uniform float u_visFactor;
-uniform int u_flags;
-uniform float u_alphaThreshold;
-
-uniform float u_npotEmulationFactor;
-uniform float u_npotEmulationXOffset;
-uniform float u_brightness;
-uniform vec4 u_fogColor;
-uniform vec3 u_tintcolor;
-uniform vec3 u_tintmodulate;
-
-in vec4 v_color;
-in float v_distance;
-in vec4 v_texCoord;
-in vec4 v_detailCoord;
-in float v_fogCoord;
-
-const float c_basepalScale = 255.0/256.0;
-const float c_basepalOffset = 0.5/256.0;
-
-const float c_zero = 0.0;
-const float c_one = 1.0;
-const float c_two = 2.0;
-const vec4 c_vec4_one = vec4(c_one);
-const float c_wrapThreshold = 0.9;
-
-layout(location=0) out vec4 fragColor;
-
-//===========================================================================
-//
-// Color to grayscale
-//
-//===========================================================================
-
-float grayscale(vec4 color)
-{
-	return dot(color.rgb, vec3(0.3, 0.56, 0.14));
-}
- 
-//===========================================================================
-//
-// Hightile tinting code. (hictinting[dapalnum]) This can be done inside the shader 
-// to avoid costly texture duplication (but needs a more modern GLSL than 1.10.)
-//
-//===========================================================================
-
-vec4 convertColor(vec4 color, int effect, vec3 tint)
-{
-#if 0
-
-	if (effect & RF_HICTINT_Grayscale)
-	{
-		float g = grayscale(color);
-		color = vec4(g, g, g, color.a);
-	}
-
-	if (effect & RF_HICTINT_Invert)
-	{
-		color = vec4(1.0 - color.r, 1.0 - color.g, 1.0 - color.b);
-	}
-	
-	vec3 tcol = color.rgb * 255.0;	// * 255.0 to make it easier to reuse the integer math.
-	tint *= 255.0;
-
-	if (effect & RF_HICTINT_Colorize)
-	{
-		tcol.b = min(((tcol.b) * tint.r) / 64.0, 255.0);
-		tcol.g = min(((tcol.g) * tint.g) / 64.0, 255.0);
-		tcol.r = min(((tcol.r) * tint.b) / 64.0, 255.0);
-	}
-
-	switch (effect & RF_HICTINT_BLENDMASK)
-	{
-		case RF_HICTINT_BLEND_Screen:
-			tcol.b = 255.0 - (((255.0 - tcol.b) * (255.0 - tint.r)) / 256.0);
-			tcol.g = 255.0 - (((255.0 - tcol.g) * (255.0 - tint.g)) / 256.0);
-			tcol.r = 255.0 - (((255.0 - tcol.r) * (255.0 - tint.b)) / 256.0);
-			break;
-		case RF_HICTINT_BLEND_Overlay:
-			tcol.b = tcol.b < 128.0? (tcol.b * tint.r) / 128.0 : 255.0 - (((255.0 - tcol.b) * (255.0 - tint.r)) / 128.0);
-			tcol.g = tcol.g < 128.0? (tcol.g * tint.g) / 128.0 : 255.0 - (((255.0 - tcol.g) * (255.0 - tint.g)) / 128.0);
-			tcol.r = tcol.r < 128.0? (tcol.r * tint.b) / 128.0 : 255.0 - (((255.0 - tcol.r) * (255.0 - tint.b)) / 128.0);
-			break;
-		case RF_HICTINT_BLEND_Hardlight:
-			tcol.b = tint.r < 128.0 ? (tcol.b * tint.r) / 128.0 : 255.0 - (((255.0 - tcol.b) * (255.0 - r)) / 128.0);
-			tcol.g = tint.g < 128.0 ? (tcol.g * tint.g) / 128.0 : 255.0 - (((255.0 - tcol.g) * (255.0 - g)) / 128.0);
-			tcol.r = tint.b < 128.0 ? (tcol.r * tint.b) / 128.0 : 255.0 - (((255.0 - tcol.r) * (255.0 - b)) / 128.0);
-			break;
-	}
-	color.rgb = tcol / 255.0;
-#endif
-	return color;
-}
-
-//===========================================================================
-//
-//
-//
-//===========================================================================
-
-void main()
-{
-	float fullbright = 0.0;
-	vec4 color;
-	if ((u_flags & RF_ColorOnly) == 0)
-	{
-		float coordX = v_texCoord.x;
-		float coordY = v_texCoord.y;
-		vec2 newCoord;
-		
-		// Coordinate adjustment for NPOT textures (something must have gone very wrong to make this necessary...)
-		if ((u_flags & RF_NPOTEmulation) != 0)
-		{
-			float period = floor(coordY / u_npotEmulationFactor);
-			coordX += u_npotEmulationXOffset * floor(mod(coordY, u_npotEmulationFactor));
-			coordY = period + mod(coordY, u_npotEmulationFactor);
-		}
-		newCoord = vec2(coordX, coordY);
-
-		// Paletted textures are stored in column major order rather than row major so coordinates need to be swapped here.
-		color = texture2D(s_texture, newCoord);
-
-		// This was further down but it really should be done before applying any kind of depth fading, not afterward.
-		vec4 detailColor = vec4(1.0);
-		if ((u_flags & RF_DetailMapping) != 0)
-		{
-			detailColor = texture2D(s_detail, v_detailCoord.xy);
-			detailColor = mix(vec4(1.0), 2.0 * detailColor, detailColor.a);
-			// Application of this differs based on render mode because for paletted rendering with palettized shade tables it can only be done after processing the shade table. We only have a palette index before.
-		}
-
-		float visibility = max(u_visFactor * v_distance - ((u_flags & RF_ShadeInterpolate) != 0.0? 0.5 : 0.0), 0.0);
-		float shade = clamp((u_shade + visibility), 0.0, u_numShades - 1.0);
-		
-
-		if ((u_flags & RF_UsePalette) != 0)
-		{
-			int palindex = int(color.r * 255.0 + 0.1); // The 0.1 is for roundoff error compensation.
-			int shadeindex = int(floor(shade));
-			float colorIndexF = texelFetch(s_palswap, ivec2(palindex, shadeindex), 0).r;
-			int colorIndex = int(colorIndexF * 255.0 + 0.1); // The 0.1 is for roundoff error compensation.
-			vec4 palettedColor = texelFetch(s_palette, ivec2(colorIndex, 0), 0);
-			
-			if ((u_flags & RF_ShadeInterpolate) != 0)
-			{
-				// Get the next shaded palette index for interpolation
-				colorIndexF = texelFetch(s_palswap, ivec2(palindex, shadeindex+1), 0).r;
-				colorIndex = int(colorIndexF * 255.0 + 0.1); // The 0.1 is for roundoff error compensation.
-				vec4 palettedColorNext = texelFetch(s_palette, ivec2(colorIndex, 0), 0);
-				float shadeFrac = mod(shade, 1.0);
-				palettedColor.rgb = mix(palettedColor.rgb, palettedColorNext.rgb, shadeFrac);
-			}
-			
-			fullbright = palettedColor.a;	// This only gets set for paletted rendering.
-	   		palettedColor.a = c_one-floor(color.r);
-	   		color = palettedColor;
-			color.rgb *= detailColor.rgb;	// with all this palettizing, this can only be applied afterward, even though it is wrong to do it this way.
-			if (fullbright == 0.0) color.rgb *= v_color.rgb; // Well, this is dead wrong but unavoidable. For colored fog it applies the light to the fog as well...
-		}
-		else
-		{
-			color.rgb *= detailColor.rgb;
-			
-			shade = clamp(shade * u_shadeDiv, 0.0, 1.0);	// u_shadeDiv is really 1/shadeDiv.
-			vec3 lightcolor = v_color.rgb;
-			if ((u_flags & RF_FogDisabled) == 0) 
-			{
-				lightcolor *= shade;
-			}
-			if ((u_flags & RF_Brightmapping) != 0)
-			{
-				vec4 brightcolor = texture2D(s_brightmap, v_texCoord.xy);
-				lightcolor = clamp(brightcolor.rgb + lightcolor, 0.0, 1.0);
-			}
-			color.rgb *= lightcolor;
-			
-			if ((u_flags & RF_FogDisabled) == 0 && u_fogColor.rgb != vec3(0))
-			{
-				// Apply the shade as a linear depth fade ramp.
-				color.rgb += u_fogColor.rgb * (1.0 - shade);
-			}
-		}
-		if (color.a < u_alphaThreshold) discard;	// it's only here that we have the alpha value available to be able to perform the alpha test.
-		
-		color.a *= v_color.a;
-	}
-	else
-	{
-		// untextured rendering
-		color = v_color;
-	}
-
-	if ((u_flags & (RF_ColorOnly|RF_GlowMapping)) == RF_GlowMapping)
-	{
-		vec4 glowColor = texture2D(s_glow, v_texCoord.xy);
-		color.rgb = mix(color.rgb, glowColor.rgb, glowColor.a);
-	}
-	
-	color.rgb = pow(color.rgb, vec3(u_brightness));
-	fragColor = color;
-}