gl: use shaders for vhs effect

this is a fuckton faster lol
the old one did a gazillion draw calls now we do two, one for the fuzzy and the 2nd for the bars as both are handled within a single shader
thanks to RRs heat effect being super similar to the vhs bars lul

src/hardware/hw_defs.h

@@ -196,6 +196,12 @@ enum
 	SHADER_PALETTE_POSTPROCESS,
 	SHADER_UI_COLORMAP_FADE,
 
+	SHADER_POSTPROCESS_WATER,
+	SHADER_POSTPROCESS_HEAT,
+
+	SHADER_VHS_FUZZ,
+	SHADER_VHS_BAR,
+
 	NUMSHADERTARGETS
 };
 

src/hardware/hw_gl.h

@@ -66,10 +66,11 @@ void GL_FlushScreenTextures(void);
 
 void GL_DrawScreenTexture(int tex, FSurfaceInfo *surf, FBITFIELD polyflags);
 void GL_DoScreenWipe(int wipeStart, int wipeEnd);
-void GL_RenderVhsEffect(fixed_t upbary, fixed_t downbary, UINT8 updistort, UINT8 downdistort, UINT8 barsize);
+void GL_RenderVhsEffect(fixed_t upbary, fixed_t downbary, UINT8 updistort, UINT8 downdistort, UINT8 barsize, boolean rewind);
 void GL_DrawScreenFinalTexture(int tex, INT32 width, INT32 height);
 
 void GL_PostImgRedraw(float points[SCREENVERTS][SCREENVERTS][2]);
+void GL_DoPostProcessor(INT32 type);
 
 boolean GL_InitShaders(void);
 void GL_LoadShader(int slot, char *code, hwdshaderstage_t stage);

src/hardware/hw_main.cpp

@@ -5992,8 +5992,7 @@ void HWR_RenderPlayerView(void)
 
 	if (HWR_UseShader())
 	{
-		if (cv_ripplewater.value)
-			GL_SetShaderInfo(HWD_SHADERINFO_LEVELTIME, (INT32)leveltime); // The water surface shader needs the leveltime.
+		GL_SetShaderInfo(HWD_SHADERINFO_LEVELTIME, (INT32)leveltime); // The water surface shader needs the leveltime.
 
 		if (cv_glmdls.value)
 		{
@@ -6002,7 +6001,7 @@ void HWR_RenderPlayerView(void)
 				const angle_t light_angle = maplighting.angle - viewangle + ANGLE_90; // I fucking hate OGL's coordinate system
 				GL_SetShaderInfo(HWD_SHADERINFO_LIGHT_X, FINECOSINE(light_angle >> ANGLETOFINESHIFT));
 				GL_SetShaderInfo(HWD_SHADERINFO_LIGHT_Y, 0);
-				GL_SetShaderInfo(HWD_SHADERINFO_LIGHT_Z,  -FINESINE(light_angle >> ANGLETOFINESHIFT));
+				GL_SetShaderInfo(HWD_SHADERINFO_LIGHT_Z, -FINESINE(light_angle >> ANGLETOFINESHIFT));
 			}
 
 			GL_SetShaderInfo(HWD_SHADERINFO_LIGHT_CONTRAST, maplighting.contrast);
@@ -6352,42 +6351,58 @@ static void HWR_DoPostProcessor(void)
 		GL_MakeScreenTexture(HWD_SCREENTEXTURE_GENERIC1);
 
 	// Drunken vision! WooOOooo~
-	// 10 by 10 grid. 2 coordinates (xy)
-	float v[SCREENVERTS][SCREENVERTS][2];
-	float disStart = (leveltime-1) + FixedToFloat(R_GetTimeFrac(RTF_LEVEL));
 
-	UINT8 x, y;
-	float WAVELENGTH;
-	float AMPLITUDE;
-	float FREQUENCY;
-
-	// Modifies the wave.
-	if (thiscam->postimg & POSTIMG_WATER)
+	// shader based, should be a bit faster!
+	if (HWR_UseShader())
 	{
-		WAVELENGTH = 5.0f;
-		AMPLITUDE = 40.0f;
-		FREQUENCY = 8.0f;
+		if (thiscam->postimg & POSTIMG_WATER)
+		{
+			GL_DoPostProcessor(POSTIMG_WATER);
+		}
+		else if (thiscam->postimg & POSTIMG_HEAT)
+		{
+			GL_DoPostProcessor(POSTIMG_HEAT);
+		}
 	}
 	else
 	{
-		WAVELENGTH = 10.0f;
-		AMPLITUDE = 60.0f;
-		FREQUENCY = 4.0f;
-	}
+		// 10 by 10 grid. 2 coordinates (xy)
+		float v[SCREENVERTS][SCREENVERTS][2];
+		float disStart = (leveltime-1) + FixedToFloat(R_GetTimeFrac(RTF_LEVEL));
 
-	//static constexpr float scale = ((float)SCREENVERTS - 1.0f) / 9.0f; // well this evals to just 1.0f and what is x / 1? kek
+		UINT8 x, y;
+		float WAVELENGTH;
+		float AMPLITUDE;
+		float FREQUENCY;
 
-	for (x = 0; x < SCREENVERTS; x++)
-	{
-		for (y = 0; y < SCREENVERTS; y++)
+		// Modifies the wave.
+		if (thiscam->postimg & POSTIMG_WATER)
 		{
-			// Change X position based on its Y position.
-			v[x][y][0] = x-4.5f + sinf(((disStart+(static_cast<float>(y) * WAVELENGTH)) / FREQUENCY)) / AMPLITUDE; // (x / scale)
-			v[x][y][1] = y-4.5f; // (y / scale)
+			WAVELENGTH = 5.0f;
+			AMPLITUDE = 40.0f;
+			FREQUENCY = 8.0f;
+		}
+		else
+		{
+			WAVELENGTH = 10.0f;
+			AMPLITUDE = 60.0f;
+			FREQUENCY = 4.0f;
 		}
-	}
 
-	GL_PostImgRedraw(v);
+		//static constexpr float scale = ((float)SCREENVERTS - 1.0f) / 9.0f; // well this evals to just 1.0f and what is x / 1? kek
+
+		for (x = 0; x < SCREENVERTS; x++)
+		{
+			for (y = 0; y < SCREENVERTS; y++)
+			{
+				// Change X position based on its Y position.
+				v[x][y][0] = x-4.5f + sinf(((disStart+(static_cast<float>(y) * WAVELENGTH)) / FREQUENCY)) / AMPLITUDE; // (x / scale)
+				v[x][y][1] = y-4.5f; // (y / scale)
+			}
+		}
+
+		GL_PostImgRedraw(v);
+	}
 
 	// Capture the screen again for screen waving on the intermission
 	if (gamestate != GS_INTERMISSION)

src/hardware/hw_main.h

@@ -145,9 +145,9 @@ FUNCINLINE static ATTRINLINE void HWR_DrawIntermissionBG(void)
 	GL_DrawScreenTexture(HWD_SCREENTEXTURE_GENERIC1, NULL, 0);
 }
 
-FUNCINLINE static ATTRINLINE void HWR_RenderVhsEffect(fixed_t upbary, fixed_t downbary, UINT8 updistort, UINT8 downdistort, UINT8 barsize)
+FUNCINLINE static ATTRINLINE void HWR_RenderVhsEffect(fixed_t upbary, fixed_t downbary, UINT8 updistort, UINT8 downdistort, UINT8 barsize, boolean rewind)
 {
-	GL_RenderVhsEffect(upbary, downbary, updistort, downdistort, barsize);
+	GL_RenderVhsEffect(upbary, downbary, updistort, downdistort, barsize, rewind);
 }
 
 FUNCINLINE static ATTRINLINE void HWR_MakeScreenTexture(void)

src/hardware/hw_shaders.c

@@ -53,6 +53,18 @@ static struct {
 	// UI colormap fade shader
 	{GLSL_DEFAULT_VERTEX_SHADER, GLSL_UI_COLORMAP_FADE_FRAGMENT_SHADER},
 
+	// water postprocess shader
+	{GLSL_DEFAULT_VERTEX_SHADER, GLSL_POSTPROCESS_FRAGMENT_WATER},
+
+	// heat postprocess shader
+	{GLSL_DEFAULT_VERTEX_SHADER, GLSL_POSTPROCESS_FRAGMENT_HEAT},
+
+	// vhs fuzz
+	{GLSL_DEFAULT_VERTEX_SHADER, GLSL_VHS_FUZZ_SHADER},
+
+	// vhs bars
+	{GLSL_DEFAULT_VERTEX_SHADER, GLSL_VHS_BAR_SHADER},
+
 	{NULL, NULL},
 };
 
@@ -444,6 +456,10 @@ customshaderxlat_t shaderxlat[] =
 	{"Sky", SHADER_SKY},
 	{"PalettePostprocess", SHADER_PALETTE_POSTPROCESS},
 	{"UIColormapFade", SHADER_UI_COLORMAP_FADE},
+	{"PostProcessWater", SHADER_POSTPROCESS_WATER},
+	{"PostProcessHeat", SHADER_POSTPROCESS_HEAT},
+	{"VHSFuzz", SHADER_VHS_FUZZ},
+	{"VHSBar", SHADER_VHS_BAR},
 	{NULL, 0},
 };
 

src/hardware/hw_shaders.h

@@ -337,6 +337,125 @@
 		"gl_FragColor = texture2D(lighttable_tex, lighttable_coord);\n" \
 	"}\0" \
 
+// these are RRs postprocess shaders
+// for water and heat
+/*
+#define GLSL_POSTPROCESS_FRAGMENT_WATER \
+	"uniform sampler2D tex;\n" \
+	"uniform float leveltime;\n" \
+	"void main(void) {\n" \
+		"vec2 uv = gl_TexCoord[0].st;\n" \
+		"float y = 1.0 - uv.y;\n" \
+		"uv.x += sin(leveltime * 2.0 + y * 20.0) * 0.01;\n" \
+		"uv = clamp(uv, vec2(0.0), vec2(0.9999));\n" \
+		"gl_FragColor = texture2D(tex, uv);\n" \
+	"}\0"
+
+#define GLSL_POSTPROCESS_FRAGMENT_HEAT \
+	"uniform sampler2D tex;\n" \
+	"uniform float leveltime;\n" \
+	"void main(void) {\n" \
+		"vec2 uv = gl_TexCoord[0].st;\n" \
+		"float y = 1.0 - uv.y;\n" \
+		"float time = leveltime * 35.0;\n" \
+		"uv.x += max(sin((time / 35.0) * 1.2 - y * 5.0) - 0.995, 0.0);\n" \
+		"uv.x -= max(sin(((time + 24.0) / 35.0) * 0.2 - y * 1.5) - 0.990, 0.0);\n" \
+		"uv = clamp(uv, vec2(0.0), vec2(0.9999));\n" \
+		"gl_FragColor = texture2D(tex, uv);\n" \
+	"}\0"
+*/
+
+// for reference
+// sin(leveltime * X + (y) + Y) * Z
+// X = Speed, Y = Vertical phase, Z = Amplitude
+
+// this matches software at 720p wonderfully
+#define GLSL_POSTPROCESS_FRAGMENT_WATER \
+	"#version 120\n" \
+	"uniform sampler2D tex;\n" \
+	"uniform vec2 scr_resolution;\n" \
+	"uniform vec2 scr_tex_size;\n" \
+	"uniform float leveltime;\n" \
+	"void main(void) {\n" \
+		"vec2 uv = gl_TexCoord[0].st;\n" \
+		"vec2 maxuv = scr_resolution / scr_tex_size;\n" \
+		"float y = 1.0 - uv.y;\n" \
+		"uv.x += sin(leveltime * 3.0 + y * 15.0) * 0.0025;\n" \
+		"uv = clamp(uv, vec2(0.0), maxuv - vec2(0.0001));\n" \
+		"gl_FragColor = texture2D(tex, uv);\n" \
+	"}\0"
+
+// like the fixed function version, this is just the water wave again
+// a bit readjusted since the shader wave is more lean
+// makes it less neausiating anyways :p
+#define GLSL_POSTPROCESS_FRAGMENT_HEAT \
+	"#version 120\n" \
+	"uniform sampler2D tex;\n" \
+	"uniform vec2 scr_resolution;\n" \
+	"uniform vec2 scr_tex_size;\n" \
+	"uniform float leveltime;\n" \
+	"void main(void) {\n" \
+		"vec2 uv = gl_TexCoord[0].st;\n" \
+		"vec2 maxuv = scr_resolution / scr_tex_size;\n" \
+		"float y = 1.0 - uv.y;\n" \
+		"uv.x += sin(leveltime * 6.0 + y * 22.5) * 0.00125;\n" \
+		"uv = clamp(uv, vec2(0.0), maxuv - vec2(0.0001));\n" \
+		"gl_FragColor = texture2D(tex, uv);\n" \
+	"}\0"
+
+// screen fuzzyness
+// basically just what we did before as a shader lul
+// thanks https://stackoverflow.com/a/4275343 for the pseudo random stuff for glsl
+#define GLSL_VHS_FUZZ_SHADER \
+	"#version 120\n" \
+	"uniform sampler2D tex;\n" \
+	"uniform vec2 scr_resolution;\n" \
+	"uniform vec2 scr_tex_size;\n" \
+	"uniform float vhs_time;\n" \
+	"uniform float scr_dup;\n" \
+	"void main(void) {\n" \
+		"vec2 uv = gl_TexCoord[0].st;\n" \
+		"vec2 maxuv = scr_resolution / scr_tex_size;\n" \
+		"float y = 1.0 - uv.y;\n" \
+		"float ystep = (2.0 / scr_resolution.y) * scr_dup / 4.0;\n" \
+		"float rand = fract(sin((floor(y / ystep) + vhs_time) * 12.9898 + 78.233) * 43758.5453);\n" \
+		"uv.x += floor(rand * 128.0) / -22000.0;\n" \
+		"uv = clamp(uv, vec2(0.0), maxuv - vec2(0.0001));\n" \
+		"gl_FragColor = texture2D(tex, uv);\n" \
+	"}\0"
+
+// repurposed the RR heat shader
+// since it kinda matched the vhs bars lul
+#define GLSL_VHS_BAR_SHADER \
+	"#version 120\n" \
+	"uniform sampler2D tex;\n" \
+	"uniform vec2 scr_resolution;\n" \
+	"uniform vec2 scr_tex_size;\n" \
+	"uniform float vhs_time;\n" \
+	"uniform float vhs_rewind;\n" \
+	"void main(void) {\n" \
+		"vec2 uv = gl_TexCoord[0].st;\n" \
+		"vec2 maxuv = scr_resolution / scr_tex_size;\n" \
+		"float y = 1.0 - uv.y;\n" \
+		"float downspd = (vhs_rewind > 0.5) ? 2.0 : 1.0;\n" \
+		"float downbar = max(sin(vhs_time * downspd - y * 5.0) - 0.95, 0.0);\n" \
+		"float upspd = (vhs_rewind > 0.5) ? 3.0 : 1.8;\n" \
+		"float upbar = max(sin((vhs_time * -1.0) * upspd - y * 5.0) - 0.95, 0.0);\n" \
+		"uv.x += (downbar) * 0.25;\n" \
+		"float updistort = (vhs_rewind > 0.5) ? 0.4125: 0.25;\n" \
+		"uv.x -= (upbar) * updistort;\n" \
+		"uv = clamp(uv, vec2(0.0), maxuv - vec2(0.0001));\n" \
+		"vec4 color = texture2D(tex, uv);\n" \
+		"float downcol = step(0.00001, downbar);\n" \
+		"float upcol = step(0.00001, upbar);\n" \
+		"color.rgb = mix(color.rgb, color.rgb * (190.0 / 255.0), downcol);\n" \
+		"color.rgb = mix(color.rgb, color.rgb * (190.0 / 255.0), upcol);\n" \
+		"color.a = mix(color.a, color.a * (250.0 / 255.0), downcol);\n" \
+		"color.a = mix(color.a, color.a * (250.0 / 255.0), upcol);\n" \
+		"gl_FragColor = color;\n" \
+	"}\0"
+
+
 // ================
 //  Fallback shaders
 // ================

src/hardware/r_opengl/r_opengl.c

@@ -761,6 +761,14 @@ typedef enum
 
 	gluniform_scr_resolution,
 
+	// postprocess stuff
+	gluniform_scr_dup,
+	gluniform_scr_tex_size,
+
+	// vhs
+	gluniform_vhs_rewind,
+	gluniform_vhs_time,
+
 	gluniform_max,
 } gluniform_t;
 
@@ -793,6 +801,9 @@ static float shader_light_z = 0.0f;
 static INT32 shader_light_contrast = 0;
 static INT32 shader_light_backlight = 0;
 
+static float shader_vhs_rewind = 1.0f;
+static float shader_vhs_time = 0.0f;
+
 // Lactozilla: Shader functions
 static boolean GL_Shader_CompileProgram(gl_shader_t *shader, GLint i);
 static void GL_Shader_SetUniforms(FSurfaceInfo *Surface, GLRGBAFloat *poly, GLRGBAFloat *tint, GLRGBAFloat *fade);
@@ -2329,6 +2340,13 @@ static void GL_Shader_SetUniforms(FSurfaceInfo *Surface, GLRGBAFloat *poly, GLRG
 		UNIFORM_1(shader->uniforms[gluniform_leveltime], shader_leveltime, pglUniform1f);
 
 		UNIFORM_2(shader->uniforms[gluniform_scr_resolution], (GLfloat)screen_width, (GLfloat)screen_height, pglUniform2f);
+		// udup is before highres scale adjustments
+		UNIFORM_1(shader->uniforms[gluniform_scr_dup], (GLfloat)vid.udup, pglUniform1f);
+		// grrrrr stupid 2.0 support.. used similar to yfix, xfix
+		UNIFORM_2(shader->uniforms[gluniform_scr_tex_size], (GLfloat)screen_texsizew, (GLfloat)screen_texsizeh, pglUniform2f);
+
+		UNIFORM_1(shader->uniforms[gluniform_vhs_rewind], shader_vhs_rewind, pglUniform1f);
+		UNIFORM_1(shader->uniforms[gluniform_vhs_time], shader_vhs_time, pglUniform1f);
 
 		#undef UNIFORM_1
 		#undef UNIFORM_2
@@ -2461,6 +2479,15 @@ static boolean GL_Shader_CompileProgram(gl_shader_t *shader, GLint i)
 
 	// misc.
 	shader->uniforms[gluniform_leveltime]             = GETUNI("leveltime");
+
+	// postprocessor stuff (water/heat effect)
+	shader->uniforms[gluniform_scr_dup]               = GETUNI("scr_dup");
+	shader->uniforms[gluniform_scr_tex_size]          = GETUNI("scr_tex_size");
+
+	// vhs stuff
+	shader->uniforms[gluniform_vhs_rewind]            = GETUNI("vhs_rewind");
+	shader->uniforms[gluniform_vhs_time]              = GETUNI("vhs_time");
+
 #undef GETUNI
 
 	// set permanent uniform values
@@ -3597,6 +3624,55 @@ INT32 GL_GetTextureUsed(void)
 	return res;
 }
 
+void GL_DoPostProcessor(INT32 type)
+{
+	float fix[8];
+	float xfix, yfix;
+
+	if (gl_enable_screen_textures != 2)
+		return;
+
+	xfix = 1/((float)screen_texsizew/(float)screen_width);
+	yfix = 1/((float)screen_texsizeh/(float)screen_height);
+
+	fix[0] = fix[1] =
+	fix[2] = fix[7] = 0.0f;
+
+	fix[3] = fix[5] = yfix;
+	fix[4] = fix[6] = xfix;
+
+	// this shouldnt be necessary, since this comes after level draw
+	// but somehow it breaks without this??
+	pglMatrixMode(GL_PROJECTION);
+	pglPushMatrix();
+	pglLoadIdentity();
+	pglMatrixMode(GL_MODELVIEW);
+	pglPushMatrix();
+	pglLoadIdentity();
+
+	GL_SetBlend(PF_NoDepthTest);
+
+	pglActiveTexture(GL_TEXTURE0);
+	pglBindTexture(GL_TEXTURE_2D, screenTextures[HWD_SCREENTEXTURE_GENERIC1]);
+	tex_downloaded = screenTextures[HWD_SCREENTEXTURE_GENERIC1];
+
+	int shader = (type == POSTIMG_WATER) ? SHADER_POSTPROCESS_WATER : SHADER_POSTPROCESS_HEAT;
+	GL_SetShader(HWR_GetShaderFromTarget(shader));
+	GL_Shader_SetUniforms(NULL, NULL, NULL, NULL);
+	pglColor4ubv(white);
+
+	pglTexCoordPointer(2, GL_FLOAT, 0, fix);
+	pglVertexPointer(3, GL_FLOAT, 0, defaultscreenVerts);
+	pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+
+	GL_UnSetShader();
+
+	pglMatrixMode(GL_PROJECTION);
+	pglPopMatrix();
+	pglMatrixMode(GL_MODELVIEW);
+	pglPopMatrix();
+}
+
 void GL_PostImgRedraw(float points[SCREENVERTS][SCREENVERTS][2])
 {
 	INT32 x, y;
@@ -3716,7 +3792,6 @@ void GL_DrawScreenTexture(int tex, FSurfaceInfo *surf, FBITFIELD polyflags)
 	tex_downloaded = screenTextures[tex];
 }
 
-
 // Do screen fades!
 void GL_DoScreenWipe(int wipeStart, int wipeEnd)
 {
@@ -3791,120 +3866,184 @@ void GL_DoScreenWipe(int wipeStart, int wipeEnd)
 	tex_downloaded = screenTextures[wipeEnd];
 }
 
-void GL_RenderVhsEffect(fixed_t upbary, fixed_t downbary, UINT8 updistort, UINT8 downdistort, UINT8 barsize)
+void GL_RenderVhsEffect(fixed_t upbary, fixed_t downbary, UINT8 updistort, UINT8 downdistort, UINT8 barsize, boolean rewind)
 {
 	float xfix, yfix;
 	float fix[8];
-	float i;
 
 	if (gl_enable_screen_textures != 2)
 		return;
 
-	GLubyte color[4] = {255, 255, 255, 255};
-
-	float screenVerts[12] =
-	{
-		-1.0f, -1.0f, 1.0f,
-		-1.0f,  1.0f, 1.0f,
-		 1.0f,  1.0f, 1.0f,
-		 1.0f, -1.0f, 1.0f
-	};
-
 	const GLfloat scrwf = (float)screen_width;
-	const GLfloat scrwh = (float)screen_height;
+	const GLfloat scrhf = (float)screen_height;
 
 	xfix = 1/((float)screen_texsizew/scrwf);
-	yfix = 1/((float)screen_texsizeh/scrwh);
+	yfix = 1/((float)screen_texsizeh/scrhf);
 
-	GL_SetBlend(PF_Modulated|PF_Translucent|PF_NoDepthTest);
-
-	// Slight fuzziness
-	GL_MakeScreenTexture(HWD_SCREENTEXTURE_VHS);
-	pglBindTexture(GL_TEXTURE_2D, screenTextures[HWD_SCREENTEXTURE_VHS]);
-
-	uint32_t r = rand();
-
-	const float ystep = 2.f/scrwh * (float)vid.udup/4.f;
-
-	for (i = 0; i < 1; i += ystep)
+	// uses shaders to replicate the effect
+	// thanks RR for their heat effect being basically the vhs bars, made this lots easier lul
+	if (HWR_UseShader())
 	{
-		// avoid calling rand thousands of times
-		r ^= r >> 13;
-		r ^= r >> 11;
-		r ^= r << 21;
+		// leveltime pauses with the game so we need to keep our own ticker here
+		static tic_t lleveltime = 0;
+		if (renderisnewtic) lleveltime++;
+		shader_vhs_time = (((float)(lleveltime-1)) + FIXED_TO_FLOAT(R_GetTimeFrac(RTF_CAMERA))) / TICRATE; // RTF_CAMERA interpolates during pause gladly...
 
-		fix[2] = (float)(r & 127) / -22000.f * xfix;
-		fix[0] = fix[2];
-		fix[6] = fix[0] + xfix;
-		fix[4] = fix[2] + xfix;
-		fix[1] = fix[7] = i*yfix;
-		fix[3] = fix[5] = (i+0.015f)*yfix;
+		// easier to account for within the shader
+		shader_vhs_rewind = rewind ? 1.0f : 0.0f;
 
-		screenVerts[1] = screenVerts[10] = 2*i - 1.0f;
-		screenVerts[4] = screenVerts[7] = screenVerts[1] + 0.03f;
+		fix[0] = fix[1] =
+		fix[2] = fix[7] = 0.0f;
 
+		fix[3] = fix[5] = yfix;
+		fix[4] = fix[6] = xfix;
+
+		GL_SetBlend(PF_NoDepthTest);
+
+		// Slight fuzziness
+		GL_MakeScreenTexture(HWD_SCREENTEXTURE_VHS);
+		pglActiveTexture(GL_TEXTURE0);
+		pglBindTexture(GL_TEXTURE_2D, screenTextures[HWD_SCREENTEXTURE_VHS]);
+		tex_downloaded = screenTextures[HWD_SCREENTEXTURE_VHS];
+
+		GL_SetShader(HWR_GetShaderFromTarget(SHADER_VHS_FUZZ));
+		GL_Shader_SetUniforms(NULL, NULL, NULL, NULL);
+		pglColor4ubv(white);
+
+		pglEnableClientState(GL_TEXTURE_COORD_ARRAY);
+		pglTexCoordPointer(2, GL_FLOAT, 0, fix);
+		pglVertexPointer(3, GL_FLOAT, 0, defaultscreenVerts);
+		pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+
+		GL_UnSetShader();
+
+		// Upward and Downward bars
+		// theyre combined since the original shader also did this
+		// also saves us another screen copy + draw anyways
+		GL_MakeScreenTexture(HWD_SCREENTEXTURE_VHS);
+		pglActiveTexture(GL_TEXTURE0);
+		pglBindTexture(GL_TEXTURE_2D, screenTextures[HWD_SCREENTEXTURE_VHS]);
+		tex_downloaded = screenTextures[HWD_SCREENTEXTURE_VHS];
+
+		GL_SetShader(HWR_GetShaderFromTarget(SHADER_VHS_BAR));
+		GL_Shader_SetUniforms(NULL, NULL, NULL, NULL);
+		pglColor4ubv(white);
+
+		pglEnableClientState(GL_TEXTURE_COORD_ARRAY);
+		pglTexCoordPointer(2, GL_FLOAT, 0, fix);
+		pglVertexPointer(3, GL_FLOAT, 0, defaultscreenVerts);
+		pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+
+		GL_UnSetShader();
+
+	}
+	else // fallback fixed function version, this is quite slow
+	{
+		float i;
+
+		GLubyte color[4] = {255, 255, 255, 255};
+
+		float screenVerts[12] =
+		{
+			-1.0f, -1.0f, 1.0f,
+			-1.0f,  1.0f, 1.0f,
+			1.0f,  1.0f, 1.0f,
+			1.0f, -1.0f, 1.0f
+		};
+
+		xfix = 1/((float)screen_texsizew/scrwf);
+		yfix = 1/((float)screen_texsizeh/scrhf);
+
+		GL_SetBlend(PF_Modulated|PF_Translucent|PF_NoDepthTest);
+
+		// Slight fuzziness
+		GL_MakeScreenTexture(HWD_SCREENTEXTURE_VHS);
+		pglBindTexture(GL_TEXTURE_2D, screenTextures[HWD_SCREENTEXTURE_VHS]);
+
+		uint32_t r = rand();
+
+		const float ystep = 2.f/scrhf * (float)vid.udup/4.f;
+
+		for (i = 0; i < 1; i += ystep)
+		{
+			// avoid calling rand thousands of times
+			r ^= r >> 13;
+			r ^= r >> 11;
+			r ^= r << 21;
+
+			fix[2] = (float)(r & 127) / -22000.f * xfix;
+			fix[0] = fix[2];
+			fix[6] = fix[0] + xfix;
+			fix[4] = fix[2] + xfix;
+			fix[1] = fix[7] = i*yfix;
+			fix[3] = fix[5] = (i+0.015f)*yfix;
+
+			screenVerts[1] = screenVerts[10] = 2*i - 1.0f;
+			screenVerts[4] = screenVerts[7] = screenVerts[1] + 0.03f;
+
+			pglColor4ubv(color);
+
+			pglTexCoordPointer(2, GL_FLOAT, 0, fix);
+			pglVertexPointer(3, GL_FLOAT, 0, screenVerts);
+			pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+		}
+
+		// Upward bar
+		GL_MakeScreenTexture(HWD_SCREENTEXTURE_VHS);
+		pglBindTexture(GL_TEXTURE_2D, screenTextures[HWD_SCREENTEXTURE_VHS]);
+
+		color[0] = color[1] = color[2] = 190;
+		color[3] = 250;
 		pglColor4ubv(color);
 
+		fix[0] = 0.0f;
+		fix[6] = xfix;
+		fix[2] = (float)updistort / scrwf * xfix;
+		fix[4] = fix[2] + fix[6];
+
+		screenVerts[1] = screenVerts[10] = 2.0f*upbary/scrhf - 1.0f;
+		screenVerts[4] = screenVerts[7] = screenVerts[1] + (float)barsize/scrhf;
+
+		fix[1] = fix[7] = (float)upbary/scrhf * yfix;
+		fix[3] = fix[5] = fix[1] + (float)barsize/2/scrhf * yfix;
+
+		pglTexCoordPointer(2, GL_FLOAT, 0, fix);
+		pglVertexPointer(3, GL_FLOAT, 0, screenVerts);
+		pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+
+		fix[1] = fix[7] += (fix[3] - fix[7])*2;
+		screenVerts[1] = screenVerts[10] += (screenVerts[4] - screenVerts[1])*2;
+
+		pglTexCoordPointer(2, GL_FLOAT, 0, fix);
+		pglVertexPointer(3, GL_FLOAT, 0, screenVerts);
+		pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+
+		// Downward bar
+		GL_MakeScreenTexture(HWD_SCREENTEXTURE_VHS);
+		pglBindTexture(GL_TEXTURE_2D, screenTextures[HWD_SCREENTEXTURE_VHS]);
+
+		fix[0] = 0.0f;
+		fix[6] = xfix;
+		fix[2] = (float)downdistort / scrwf * -xfix;
+		fix[4] = fix[2] + fix[6];
+
+		screenVerts[1] = screenVerts[10] = 2.0f*downbary/scrhf - 1.0f;
+		screenVerts[4] = screenVerts[7] = screenVerts[1] + (float)barsize/scrhf;
+
+		fix[1] = fix[7] = (float)downbary/scrhf * yfix;
+		fix[3] = fix[5] = fix[1] + (float)barsize/2/scrhf * yfix;
+
+		pglTexCoordPointer(2, GL_FLOAT, 0, fix);
+		pglVertexPointer(3, GL_FLOAT, 0, screenVerts);
+		pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+
+		fix[1] = fix[7] += (fix[3] - fix[7])*2;
+		screenVerts[1] = screenVerts[10] += (screenVerts[4] - screenVerts[1])*2;
+
 		pglTexCoordPointer(2, GL_FLOAT, 0, fix);
 		pglVertexPointer(3, GL_FLOAT, 0, screenVerts);
 		pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 	}
-
-	// Upward bar
-	GL_MakeScreenTexture(HWD_SCREENTEXTURE_VHS);
-	pglBindTexture(GL_TEXTURE_2D, screenTextures[HWD_SCREENTEXTURE_VHS]);
-
-	color[0] = color[1] = color[2] = 190;
-	color[3] = 250;
-	pglColor4ubv(color);
-
-	fix[0] = 0.0f;
-	fix[6] = xfix;
-	fix[2] = (float)updistort / scrwf * xfix;
-	fix[4] = fix[2] + fix[6];
-
-	screenVerts[1] = screenVerts[10] = 2.0f*upbary/scrwh - 1.0f;
-	screenVerts[4] = screenVerts[7] = screenVerts[1] + (float)barsize/scrwh;
-
-	fix[1] = fix[7] = (float)upbary/scrwh * yfix;
-	fix[3] = fix[5] = fix[1] + (float)barsize/2/scrwh * yfix;
-
-	pglTexCoordPointer(2, GL_FLOAT, 0, fix);
-	pglVertexPointer(3, GL_FLOAT, 0, screenVerts);
-	pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
-
-	fix[1] = fix[7] += (fix[3] - fix[7])*2;
-	screenVerts[1] = screenVerts[10] += (screenVerts[4] - screenVerts[1])*2;
-
-	pglTexCoordPointer(2, GL_FLOAT, 0, fix);
-	pglVertexPointer(3, GL_FLOAT, 0, screenVerts);
-	pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
-
-	// Downward bar
-	GL_MakeScreenTexture(HWD_SCREENTEXTURE_VHS);
-	pglBindTexture(GL_TEXTURE_2D, screenTextures[HWD_SCREENTEXTURE_VHS]);
-
-	fix[0] = 0.0f;
-	fix[6] = xfix;
-	fix[2] = (float)downdistort / scrwf * -xfix;
-	fix[4] = fix[2] + fix[6];
-
-	screenVerts[1] = screenVerts[10] = 2.0f*downbary/scrwh - 1.0f;
-	screenVerts[4] = screenVerts[7] = screenVerts[1] + (float)barsize/scrwh;
-
-	fix[1] = fix[7] = (float)downbary/scrwh * yfix;
-	fix[3] = fix[5] = fix[1] + (float)barsize/2/scrwh * yfix;
-
-	pglTexCoordPointer(2, GL_FLOAT, 0, fix);
-	pglVertexPointer(3, GL_FLOAT, 0, screenVerts);
-	pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
-
-	fix[1] = fix[7] += (fix[3] - fix[7])*2;
-	screenVerts[1] = screenVerts[10] += (screenVerts[4] - screenVerts[1])*2;
-
-	pglTexCoordPointer(2, GL_FLOAT, 0, fix);
-	pglVertexPointer(3, GL_FLOAT, 0, screenVerts);
-	pglDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 }
 
 // Create a texture from the screen.

src/v_video.c

@@ -1882,7 +1882,7 @@ void V_DrawVhsEffect(boolean rewind)
 #ifdef HWRENDER
 	if (rendermode == render_opengl)
 	{
-		HWR_RenderVhsEffect(uby, dby, updistort, downdistort, barsize);
+		HWR_RenderVhsEffect(uby, dby, updistort, downdistort, barsize, rewind);
 		return;
 	}
 #endif
@@ -3619,7 +3619,7 @@ void V_DoPostProcessor(INT32 view, INT32 param)
 
 			for (y = yoffset; y < yoffset+viewheight; y++)
 			{
-				sine = (FINESINE(disStart)*5)>>FRACBITS;
+				sine = (FINESINE(disStart) * 5) >> FRACBITS;
 				newpix = abs(sine);
 
 				if (sine < 0)
@@ -3659,8 +3659,8 @@ void V_DoPostProcessor(INT32 view, INT32 param)
 					tmpscr[y*vid.width + x] = srcscr[y*vid.width+newpix]; // *(transme + (srcscr[y*vid.width+x]<<8) + srcscr[y*vid.width+newpix]);
 				}*/
 
-				disStart += 22;//the offset into the displacement map, increment each game loop
-				disStart &= FINEMASK; //clip it to FINEMASK
+				disStart += 22; // the offset into the displacement map, increment each game loop
+				disStart &= FINEMASK; // clip it to FINEMASK
 			}
 
 			UINT8 *tmp = tmpscr;