Shadow mapping render pass (#11244)

Co-authored-by: x2048 <codeforsmile@gmail.com>

2 files changed, 338 insertions, 5 deletions

diff --git a/client/shaders/object_shader/opengl_fragment.glsl b/client/shaders/object_shader/opengl_fragment.glsl
index 9a81d8185..8d6f57a44 100644
--- a/client/shaders/object_shader/opengl_fragment.glsl
+++ b/client/shaders/object_shader/opengl_fragment.glsl
@@ -23,8 +23,22 @@ const float BS = 10.0;
 const float fogStart = FOG_START;
 const float fogShadingParameter = 1.0 / (1.0 - fogStart);
 
-#if ENABLE_TONE_MAPPING
+#ifdef ENABLE_DYNAMIC_SHADOWS
+	// shadow texture
+	uniform sampler2D ShadowMapSampler;
+	// shadow uniforms
+	uniform vec3 v_LightDirection;
+	uniform float f_textureresolution;
+	uniform mat4 m_ShadowViewProj;
+	uniform float f_shadowfar;
+	uniform float f_timeofday;
+	varying float normalOffsetScale;
+	varying float adj_shadow_strength;
+	varying float cosLight;
+	varying float f_normal_length;
+#endif
 
+#if ENABLE_TONE_MAPPING
 /* Hable's UC2 Tone mapping parameters
 	A = 0.22;
 	B = 0.30;
@@ -55,11 +69,263 @@ vec4 applyToneMapping(vec4 color)
 }
 #endif
 
+#ifdef ENABLE_DYNAMIC_SHADOWS
+const float bias0 = 0.9;
+const float zPersFactor = 0.5;
+const float bias1 = 1.0 - bias0;
+
+vec4 getPerspectiveFactor(in vec4 shadowPosition)
+{
+	float pDistance = length(shadowPosition.xy);
+	float pFactor = pDistance * bias0 + bias1;
+	shadowPosition.xyz *= vec3(vec2(1.0 / pFactor), zPersFactor);
+
+	return shadowPosition;
+}
+
+// assuming near is always 1.0
+float getLinearDepth()
+{
+	return 2.0 * f_shadowfar / (f_shadowfar + 1.0 - (2.0 * gl_FragCoord.z - 1.0) * (f_shadowfar - 1.0));
+}
+
+vec3 getLightSpacePosition()
+{
+	vec4 pLightSpace;
+	float normalBias = 0.0005 * getLinearDepth() * cosLight + normalOffsetScale;
+	pLightSpace = m_ShadowViewProj * vec4(worldPosition + normalBias * normalize(vNormal), 1.0);
+	pLightSpace = getPerspectiveFactor(pLightSpace);
+	return pLightSpace.xyz * 0.5 + 0.5;
+}
+
+#ifdef COLORED_SHADOWS
+
+// c_precision of 128 fits within 7 base-10 digits
+const float c_precision = 128.0;
+const float c_precisionp1 = c_precision + 1.0;
+
+float packColor(vec3 color)
+{
+	return floor(color.b * c_precision + 0.5)
+		+ floor(color.g * c_precision + 0.5) * c_precisionp1
+		+ floor(color.r * c_precision + 0.5) * c_precisionp1 * c_precisionp1;
+}
+
+vec3 unpackColor(float value)
+{
+	vec3 color;
+	color.b = mod(value, c_precisionp1) / c_precision;
+	color.g = mod(floor(value / c_precisionp1), c_precisionp1) / c_precision;
+	color.r = floor(value / (c_precisionp1 * c_precisionp1)) / c_precision;
+	return color;
+}
+
+vec4 getHardShadowColor(sampler2D shadowsampler, vec2 smTexCoord, float realDistance)
+{
+	vec4 texDepth = texture2D(shadowsampler, smTexCoord.xy).rgba;
+
+	float visibility = step(0.0, (realDistance-2e-5) - texDepth.r);
+	vec4 result = vec4(visibility, vec3(0.0,0.0,0.0));//unpackColor(texDepth.g));
+	if (visibility < 0.1) {
+		visibility = step(0.0, (realDistance-2e-5) - texDepth.r);
+		result = vec4(visibility, unpackColor(texDepth.a));
+	}
+	return result;
+}
+
+#else
+
+float getHardShadow(sampler2D shadowsampler, vec2 smTexCoord, float realDistance)
+{
+	float texDepth = texture2D(shadowsampler, smTexCoord.xy).r;
+	float visibility = step(0.0, (realDistance-2e-5) - texDepth);
+
+	return visibility;
+}
+
+#endif
+
+#if SHADOW_FILTER == 2
+	#define PCFBOUND 3.5
+	#define PCFSAMPLES 64.0
+#elif SHADOW_FILTER == 1
+	#define PCFBOUND 1.5
+	#if defined(POISSON_FILTER)
+		#define PCFSAMPLES 32.0
+	#else
+		#define PCFSAMPLES 16.0
+	#endif
+#else
+	#define PCFBOUND 0.0
+	#if defined(POISSON_FILTER)
+		#define PCFSAMPLES 4.0
+	#else
+		#define PCFSAMPLES 1.0
+	#endif
+#endif
+
+#ifdef POISSON_FILTER
+const vec2[64] poissonDisk = vec2[64](
+	vec2(0.170019, -0.040254),
+	vec2(-0.299417, 0.791925),
+	vec2(0.645680, 0.493210),
+	vec2(-0.651784, 0.717887),
+	vec2(0.421003, 0.027070),
+	vec2(-0.817194, -0.271096),
+	vec2(-0.705374, -0.668203),
+	vec2(0.977050, -0.108615),
+	vec2(0.063326, 0.142369),
+	vec2(0.203528, 0.214331),
+	vec2(-0.667531, 0.326090),
+	vec2(-0.098422, -0.295755),
+	vec2(-0.885922, 0.215369),
+	vec2(0.566637, 0.605213),
+	vec2(0.039766, -0.396100),
+	vec2(0.751946, 0.453352),
+	vec2(0.078707, -0.715323),
+	vec2(-0.075838, -0.529344),
+	vec2(0.724479, -0.580798),
+	vec2(0.222999, -0.215125),
+	vec2(-0.467574, -0.405438),
+	vec2(-0.248268, -0.814753),
+	vec2(0.354411, -0.887570),
+	vec2(0.175817, 0.382366),
+	vec2(0.487472, -0.063082),
+	vec2(0.355476, 0.025357),
+	vec2(-0.084078, 0.898312),
+	vec2(0.488876, -0.783441),
+	vec2(0.470016, 0.217933),
+	vec2(-0.696890, -0.549791),
+	vec2(-0.149693, 0.605762),
+	vec2(0.034211, 0.979980),
+	vec2(0.503098, -0.308878),
+	vec2(-0.016205, -0.872921),
+	vec2(0.385784, -0.393902),
+	vec2(-0.146886, -0.859249),
+	vec2(0.643361, 0.164098),
+	vec2(0.634388, -0.049471),
+	vec2(-0.688894, 0.007843),
+	vec2(0.464034, -0.188818),
+	vec2(-0.440840, 0.137486),
+	vec2(0.364483, 0.511704),
+	vec2(0.034028, 0.325968),
+	vec2(0.099094, -0.308023),
+	vec2(0.693960, -0.366253),
+	vec2(0.678884, -0.204688),
+	vec2(0.001801, 0.780328),
+	vec2(0.145177, -0.898984),
+	vec2(0.062655, -0.611866),
+	vec2(0.315226, -0.604297),
+	vec2(-0.780145, 0.486251),
+	vec2(-0.371868, 0.882138),
+	vec2(0.200476, 0.494430),
+	vec2(-0.494552, -0.711051),
+	vec2(0.612476, 0.705252),
+	vec2(-0.578845, -0.768792),
+	vec2(-0.772454, -0.090976),
+	vec2(0.504440, 0.372295),
+	vec2(0.155736, 0.065157),
+	vec2(0.391522, 0.849605),
+	vec2(-0.620106, -0.328104),
+	vec2(0.789239, -0.419965),
+	vec2(-0.545396, 0.538133),
+	vec2(-0.178564, -0.596057)
+);
+
+#ifdef COLORED_SHADOWS
+
+vec4 getShadowColor(sampler2D shadowsampler, vec2 smTexCoord, float realDistance)
+{
+	vec2 clampedpos;
+	vec4 visibility = vec4(0.0);
+
+	float texture_size = 1.0 / (f_textureresolution * 0.5);
+	int init_offset = int(floor(mod(((smTexCoord.x * 34.0) + 1.0) * smTexCoord.y, 64.0-PCFSAMPLES)));
+	int end_offset = int(PCFSAMPLES) + init_offset;
+
+	for (int x = init_offset; x < end_offset; x++) {
+		clampedpos = poissonDisk[x] * texture_size * SOFTSHADOWRADIUS + smTexCoord.xy;
+		visibility += getHardShadowColor(shadowsampler, clampedpos.xy, realDistance);
+	}
+
+	return visibility / PCFSAMPLES;
+}
+
+#else
+
+float getShadow(sampler2D shadowsampler, vec2 smTexCoord, float realDistance)
+{
+	vec2 clampedpos;
+	float visibility = 0.0;
+
+	float texture_size = 1.0 / (f_textureresolution * 0.5);
+	int init_offset = int(floor(mod(((smTexCoord.x * 34.0) + 1.0) * smTexCoord.y, 64.0-PCFSAMPLES)));
+	int end_offset = int(PCFSAMPLES) + init_offset;
+
+	for (int x = init_offset; x < end_offset; x++) {
+		clampedpos = poissonDisk[x] * texture_size * SOFTSHADOWRADIUS + smTexCoord.xy;
+		visibility += getHardShadow(shadowsampler, clampedpos.xy, realDistance);
+	}
+
+	return visibility / PCFSAMPLES;
+}
+
+#endif
+
+#else
+/* poisson filter disabled */
+
+#ifdef COLORED_SHADOWS
+
+vec4 getShadowColor(sampler2D shadowsampler, vec2 smTexCoord, float realDistance)
+{
+	vec2 clampedpos;
+	vec4 visibility = vec4(0.0);
+	float sradius=0.0;
+	if( PCFBOUND>0)
+		sradius = SOFTSHADOWRADIUS / PCFBOUND;  
+	float texture_size = 1.0 / (f_textureresolution * 0.5);
+	float y, x;
+	// basic PCF filter
+	for (y = -PCFBOUND; y <= PCFBOUND; y += 1.0)
+	for (x = -PCFBOUND; x <= PCFBOUND; x += 1.0) {
+		clampedpos = vec2(x,y) * texture_size* sradius +  smTexCoord.xy;
+		visibility += getHardShadowColor(shadowsampler, clampedpos.xy, realDistance);
+	}
+
+	return visibility / PCFSAMPLES;
+}
+
+#else
+float getShadow(sampler2D shadowsampler, vec2 smTexCoord, float realDistance)
+{
+	vec2 clampedpos;
+	float visibility = 0.0;
+	float sradius=0.0;
+	if( PCFBOUND>0)
+		sradius = SOFTSHADOWRADIUS / PCFBOUND;  
+	
+	float texture_size = 1.0 / (f_textureresolution * 0.5);
+	float y, x;
+	// basic PCF filter
+	for (y = -PCFBOUND; y <= PCFBOUND; y += 1.0)
+	for (x = -PCFBOUND; x <= PCFBOUND; x += 1.0) {
+		clampedpos =  vec2(x,y) * texture_size * sradius + smTexCoord.xy;
+		visibility += getHardShadow(shadowsampler, clampedpos.xy, realDistance);
+	}
+
+	return visibility / PCFSAMPLES;
+}
+
+#endif
+
+#endif
+#endif
+
 void main(void)
 {
 	vec3 color;
 	vec2 uv = varTexCoord.st;
-
 	vec4 base = texture2D(baseTexture, uv).rgba;
 
 #ifdef USE_DISCARD
@@ -72,13 +338,34 @@ void main(void)
 #endif
 
 	color = base.rgb;
-
 	vec4 col = vec4(color.rgb, base.a);
-
 	col.rgb *= varColor.rgb;
-
 	col.rgb *= emissiveColor.rgb * vIDiff;
 
+#ifdef ENABLE_DYNAMIC_SHADOWS
+	float shadow_int = 0.0;
+	vec3 shadow_color = vec3(0.0, 0.0, 0.0);
+	vec3 posLightSpace = getLightSpacePosition();
+
+#ifdef COLORED_SHADOWS
+	vec4 visibility = getShadowColor(ShadowMapSampler, posLightSpace.xy, posLightSpace.z);
+	shadow_int = visibility.r;
+	shadow_color = visibility.gba;
+#else
+	shadow_int = getShadow(ShadowMapSampler, posLightSpace.xy, posLightSpace.z);
+#endif
+
+	if (f_normal_length != 0 && cosLight <= 0.001) {
+		shadow_int = clamp(shadow_int + 0.5 * abs(cosLight), 0.0, 1.0);
+	}
+
+	shadow_int = 1.0 - (shadow_int * adj_shadow_strength);
+
+	col.rgb = mix(shadow_color, col.rgb, shadow_int) * shadow_int;
+#endif
+
+
+
 #if ENABLE_TONE_MAPPING
 	col = applyToneMapping(col);
 #endif
diff --git a/client/shaders/object_shader/opengl_vertex.glsl b/client/shaders/object_shader/opengl_vertex.glsl
index f26224e82..f135ab9dc 100644
--- a/client/shaders/object_shader/opengl_vertex.glsl
+++ b/client/shaders/object_shader/opengl_vertex.glsl
@@ -13,12 +13,37 @@ varying mediump vec2 varTexCoord;
 centroid varying vec2 varTexCoord;
 #endif
 
+#ifdef ENABLE_DYNAMIC_SHADOWS
+	// shadow uniforms
+	uniform vec3 v_LightDirection;
+	uniform float f_textureresolution;
+	uniform mat4 m_ShadowViewProj;
+	uniform float f_shadowfar;
+	uniform float f_shadow_strength;
+	uniform float f_timeofday;
+	varying float cosLight;
+	varying float normalOffsetScale;
+	varying float adj_shadow_strength;
+	varying float f_normal_length;
+#endif
+
 varying vec3 eyeVec;
 varying float vIDiff;
 
 const float e = 2.718281828459;
 const float BS = 10.0;
 
+#ifdef ENABLE_DYNAMIC_SHADOWS
+// custom smoothstep implementation because it's not defined in glsl1.2
+// https://docs.gl/sl4/smoothstep
+float mtsmoothstep(in float edge0, in float edge1, in float x)
+{
+	float t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
+	return t * t * (3.0 - 2.0 * t);
+}
+#endif
+
+
 float directional_ambient(vec3 normal)
 {
 	vec3 v = normal * normal;
@@ -54,4 +79,25 @@ void main(void)
 #else
 	varColor = inVertexColor;
 #endif
+
+#ifdef ENABLE_DYNAMIC_SHADOWS
+
+	cosLight = max(0.0, dot(vNormal, -v_LightDirection));
+	float texelSize = 0.51;
+	float slopeScale = clamp(1.0 - cosLight, 0.0, 1.0);
+	normalOffsetScale = texelSize * slopeScale;
+	if (f_timeofday < 0.2) {
+		adj_shadow_strength = f_shadow_strength * 0.5 *
+			(1.0 - mtsmoothstep(0.18, 0.2, f_timeofday));
+	} else if (f_timeofday >= 0.8) {
+		adj_shadow_strength = f_shadow_strength * 0.5 *
+			mtsmoothstep(0.8, 0.83, f_timeofday);
+	} else {
+		adj_shadow_strength = f_shadow_strength *
+			mtsmoothstep(0.20, 0.25, f_timeofday) *
+			(1.0 - mtsmoothstep(0.7, 0.8, f_timeofday));
+	}
+	f_normal_length = length(vNormal);
+
+#endif
 }