Adjust shadowmap distortion to use entire SM texture (minetest#12166)

client/shaders/nodes_shader/opengl_fragment.glsl

@@ -17,6 +17,7 @@ uniform float animationTimer;
  uniform mat4 m_ShadowViewProj;
  uniform float f_shadowfar;
  uniform float f_shadow_strength;
+ uniform vec4 CameraPos;
  varying float normalOffsetScale;
  varying float adj_shadow_strength;
  varying float cosLight;
@@ -53,12 +54,13 @@ uniform float zPerspectiveBias;
 
 vec4 getPerspectiveFactor(in vec4 shadowPosition)
 {
-
- float pDistance = length(shadowPosition.xy);
+ vec2 s = vec2(shadowPosition.x > CameraPos.x ? 1.0 : -1.0, shadowPosition.y > CameraPos.y ? 1.0 : -1.0);
+ vec2 l = s * (shadowPosition.xy - CameraPos.xy) / (1.0 - s * CameraPos.xy);
+ float pDistance = length(l);
  float pFactor = pDistance * xyPerspectiveBias0 + xyPerspectiveBias1;
-
- shadowPosition.xyz *= vec3(vec2(1.0 / pFactor), zPerspectiveBias);
-
+ l /= pFactor;
+ shadowPosition.xy = CameraPos.xy * (1.0 - l) + s * l;
+ shadowPosition.z *= zPerspectiveBias;
  return shadowPosition;
 }
 
@@ -171,21 +173,20 @@ float getHardShadowDepth(sampler2D shadowsampler, vec2 smTexCoord, float realDis
 
 float getBaseLength(vec2 smTexCoord)
 {
- float l = length(2.0 * smTexCoord.xy - 1.0); // length in texture coords
+ float l = length(2.0 * smTexCoord.xy - 1.0 - CameraPos.xy); // length in texture coords
  return xyPerspectiveBias1 / (1.0 / l - xyPerspectiveBias0); // return to undistorted coords
 }
 
 float getDeltaPerspectiveFactor(float l)
 {
- return 0.1 / (xyPerspectiveBias0 * l + xyPerspectiveBias1); // original distortion factor, divided by 10
+ return 0.04 * pow(512.0 / f_textureresolution, 0.4) / (xyPerspectiveBias0 * l + xyPerspectiveBias1); // original distortion factor, divided by 10
 }
 
 float getPenumbraRadius(sampler2D shadowsampler, vec2 smTexCoord, float realDistance, float multiplier)
 {
  float baseLength = getBaseLength(smTexCoord);
  float perspectiveFactor;
 
- if (PCFBOUND == 0.0) return 0.0;
  // Return fast if sharp shadows are requested
  if (PCFBOUND == 0.0)
  return 0.0;
@@ -489,11 +490,13 @@ void main(void)
  vec3 shadow_color = vec3(0.0, 0.0, 0.0);
  vec3 posLightSpace = getLightSpacePosition();
 
- float distance_rate = (1 - pow(clamp(2.0 * length(posLightSpace.xy - 0.5),0.0,1.0), 50.0));
+ float distance_rate = (1.0 - pow(clamp(2.0 * length(posLightSpace.xy - 0.5),0.0,1.0), 10.0));
+ if (max(abs(posLightSpace.x - 0.5), abs(posLightSpace.y - 0.5)) > 0.5)
+ distance_rate = 0.0;
  float f_adj_shadow_strength = max(adj_shadow_strength-mtsmoothstep(0.9,1.1, posLightSpace.z),0.0);
 
  if (distance_rate > 1e-7) {
- 
+
 #ifdef COLORED_SHADOWS
  vec4 visibility;
  if (cosLight > 0.0)
@@ -527,7 +530,7 @@ void main(void)
  }
 
  shadow_int *= f_adj_shadow_strength;
- 
+
  // calculate fragment color from components:
  col.rgb =
  adjusted_night_ratio * col.rgb + // artificial light

client/shaders/object_shader/opengl_fragment.glsl

@@ -6,41 +6,49 @@ uniform vec4 skyBgColor;
 uniform float fogDistance;
 uniform vec3 eyePosition;
 
+// The cameraOffset is the current center of the visible world.
+uniform vec3 cameraOffset;
+uniform float animationTimer;
+#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_shadow_strength;
+ uniform vec4 CameraPos;
+ varying float normalOffsetScale;
+ varying float adj_shadow_strength;
+ varying float cosLight;
+ varying float f_normal_length;
+#endif
+
+
 varying vec3 vNormal;
 varying vec3 vPosition;
+// World position in the visible world (i.e. relative to the cameraOffset.)
+// This can be used for many shader effects without loss of precision.
+// If the absolute position is required it can be calculated with
+// cameraOffset + worldPosition (for large coordinates the limits of float
+// precision must be considered).
 varying vec3 worldPosition;
 varying lowp vec4 varColor;
 #ifdef GL_ES
 varying mediump vec2 varTexCoord;
 #else
 centroid varying vec2 varTexCoord;
 #endif
-
 varying vec3 eyeVec;
 varying float nightRatio;
 
 varying float vIDiff;
 
-const float e = 2.718281828459;
-const float BS = 10.0;
 const float fogStart = FOG_START;
 const float fogShadingParameter = 1.0 / (1.0 - fogStart);
 
-#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;
- uniform float f_shadow_strength;
- varying float normalOffsetScale;
- varying float adj_shadow_strength;
- varying float cosLight;
- varying float f_normal_length;
-#endif
+
 
 #ifdef ENABLE_DYNAMIC_SHADOWS
 uniform float xyPerspectiveBias0;
@@ -49,15 +57,22 @@ uniform float zPerspectiveBias;
 
 vec4 getPerspectiveFactor(in vec4 shadowPosition)
 {
-
- float pDistance = length(shadowPosition.xy);
+ vec2 s = vec2(shadowPosition.x > CameraPos.x ? 1.0 : -1.0, shadowPosition.y > CameraPos.y ? 1.0 : -1.0);
+ vec2 l = s * (shadowPosition.xy - CameraPos.xy) / (1.0 - s * CameraPos.xy);
+ float pDistance = length(l);
  float pFactor = pDistance * xyPerspectiveBias0 + xyPerspectiveBias1;
-
- shadowPosition.xyz *= vec3(vec2(1.0 / pFactor), zPerspectiveBias);
-
+ l /= pFactor;
+ shadowPosition.xy = CameraPos.xy * (1.0 - l) + s * l;
+ shadowPosition.z *= zPerspectiveBias;
  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;
@@ -161,13 +176,13 @@ float getHardShadowDepth(sampler2D shadowsampler, vec2 smTexCoord, float realDis
 
 float getBaseLength(vec2 smTexCoord)
 {
- float l = length(2.0 * smTexCoord.xy - 1.0); // length in texture coords
+ float l = length(2.0 * smTexCoord.xy - 1.0 - CameraPos.xy); // length in texture coords
  return xyPerspectiveBias1 / (1.0 / l - xyPerspectiveBias0); // return to undistorted coords
 }
 
 float getDeltaPerspectiveFactor(float l)
 {
- return 0.1 / (xyPerspectiveBias0 * l + xyPerspectiveBias1); // original distortion factor, divided by 10
+ return 0.04 * pow(512.0 / f_textureresolution, 0.4) / (xyPerspectiveBias0 * l + xyPerspectiveBias1); // original distortion factor, divided by 10
 }
 
 float getPenumbraRadius(sampler2D shadowsampler, vec2 smTexCoord, float realDistance, float multiplier)
@@ -178,7 +193,7 @@ float getPenumbraRadius(sampler2D shadowsampler, vec2 smTexCoord, float realDist
  // Return fast if sharp shadows are requested
  if (PCFBOUND == 0.0)
  return 0.0;
- 
+
  if (SOFTSHADOWRADIUS <= 1.0) {
  perspectiveFactor = getDeltaPerspectiveFactor(baseLength);
  return max(2 * length(smTexCoord.xy) * 2048 / f_textureresolution / pow(perspectiveFactor, 3), SOFTSHADOWRADIUS);
@@ -418,6 +433,7 @@ float getShadow(sampler2D shadowsampler, vec2 smTexCoord, float realDistance)
 #endif
 
 #if ENABLE_TONE_MAPPING
+
 /* Hable's UC2 Tone mapping parameters
  A = 0.22;
  B = 0.30;
@@ -448,12 +464,14 @@ vec4 applyToneMapping(vec4 color)
 }
 #endif
 
+
+
 void main(void)
 {
  vec3 color;
  vec2 uv = varTexCoord.st;
- vec4 base = texture2D(baseTexture, uv).rgba;
 
+ vec4 base = texture2D(baseTexture, uv).rgba;
  // If alpha is zero, we can just discard the pixel. This fixes transparency
  // on GPUs like GC7000L, where GL_ALPHA_TEST is not implemented in mesa,
  // and also on GLES 2, where GL_ALPHA_TEST is missing entirely.
@@ -467,8 +485,7 @@ void main(void)
 #endif
 
  color = base.rgb;
- vec4 col = vec4(color.rgb, base.a);
- col.rgb *= varColor.rgb;
+ vec4 col = vec4(color.rgb * varColor.rgb, 1.0);
  col.rgb *= vIDiff;
 
 #ifdef ENABLE_DYNAMIC_SHADOWS
@@ -477,11 +494,13 @@ void main(void)
  vec3 shadow_color = vec3(0.0, 0.0, 0.0);
  vec3 posLightSpace = getLightSpacePosition();
 
- float distance_rate = (1 - pow(clamp(2.0 * length(posLightSpace.xy - 0.5),0.0,1.0), 50.0));
+ float distance_rate = (1.0 - pow(clamp(2.0 * length(posLightSpace.xy - 0.5),0.0,1.0), 10.0));
+ if (max(abs(posLightSpace.x - 0.5), abs(posLightSpace.y - 0.5)) > 0.5)
+ distance_rate = 0.0;
  float f_adj_shadow_strength = max(adj_shadow_strength-mtsmoothstep(0.9,1.1, posLightSpace.z),0.0);
 
  if (distance_rate > 1e-7) {
- 
+
 #ifdef COLORED_SHADOWS
  vec4 visibility;
  if (cosLight > 0.0)
@@ -506,8 +525,8 @@ void main(void)
  // Power ratio was measured on torches in MTG (brightness = 14).
  float adjusted_night_ratio = pow(max(0.0, nightRatio), 0.6);
 
- // cosine of the normal-to-light angle when
- // we start to apply self-shadowing
+ // Apply self-shadowing when light falls at a narrow angle to the surface
+ // Cosine of the cut-off angle.
  const float self_shadow_cutoff_cosine = 0.14;
  if (f_normal_length != 0 && cosLight < self_shadow_cutoff_cosine) {
  shadow_int = max(shadow_int, 1 - clamp(cosLight, 0.0, self_shadow_cutoff_cosine)/self_shadow_cutoff_cosine);
@@ -541,5 +560,7 @@ void main(void)
  float clarity = clamp(fogShadingParameter
  - fogShadingParameter * length(eyeVec) / fogDistance, 0.0, 1.0);
  col = mix(skyBgColor, col, clarity);
- gl_FragColor = vec4(col.rgb, base.a);
+ col = vec4(col.rgb, base.a);
+
+ gl_FragColor = col;
 }

client/shaders/shadow_shaders/pass1_trans_vertex.glsl

@@ -1,4 +1,5 @@
 uniform mat4 LightMVP; // world matrix
+uniform vec4 CameraPos;
 varying vec4 tPos;
 #ifdef COLORED_SHADOWS
 varying vec3 varColor;
@@ -10,10 +11,13 @@ uniform float zPerspectiveBias;
 
 vec4 getPerspectiveFactor(in vec4 shadowPosition)
 {
- float pDistance = length(shadowPosition.xy);
+ vec2 s = vec2(shadowPosition.x > CameraPos.x ? 1.0 : -1.0, shadowPosition.y > CameraPos.y ? 1.0 : -1.0);
+ vec2 l = s * (shadowPosition.xy - CameraPos.xy) / (1.0 - s * CameraPos.xy);
+ float pDistance = length(l);
  float pFactor = pDistance * xyPerspectiveBias0 + xyPerspectiveBias1;
- shadowPosition.xyz *= vec3(vec2(1.0 / pFactor), zPerspectiveBias);
-
+ l /= pFactor;
+ shadowPosition.xy = CameraPos.xy * (1.0 - l) + s * l;
+ shadowPosition.z *= zPerspectiveBias;
  return shadowPosition;
 }
 

client/shaders/shadow_shaders/pass1_vertex.glsl

@@ -1,4 +1,5 @@
 uniform mat4 LightMVP; // world matrix
+uniform vec4 CameraPos; // camera position
 varying vec4 tPos;
 
 uniform float xyPerspectiveBias0;
@@ -7,10 +8,13 @@ uniform float zPerspectiveBias;
 
 vec4 getPerspectiveFactor(in vec4 shadowPosition)
 {
- float pDistance = length(shadowPosition.xy);
+ vec2 s = vec2(shadowPosition.x > CameraPos.x ? 1.0 : -1.0, shadowPosition.y > CameraPos.y ? 1.0 : -1.0);
+ vec2 l = s * (shadowPosition.xy - CameraPos.xy) / (1.0 - s * CameraPos.xy);
+ float pDistance = length(l);
  float pFactor = pDistance * xyPerspectiveBias0 + xyPerspectiveBias1;
- shadowPosition.xyz *= vec3(vec2(1.0 / pFactor), zPerspectiveBias);
-
+ l /= pFactor;
+ shadowPosition.xy = CameraPos.xy * (1.0 - l) + s * l;
+ shadowPosition.z *= zPerspectiveBias;
  return shadowPosition;
 }
 

src/client/clientmap.cpp

@@ -862,20 +862,14 @@ void ClientMap::renderMapShadows(video::IVideoDriver *driver,
 /*
  Custom update draw list for the pov of shadow light.
 */
-void ClientMap::updateDrawListShadow(const v3f &shadow_light_pos, const v3f &shadow_light_dir, float shadow_range)
+void ClientMap::updateDrawListShadow(v3f shadow_light_pos, v3f shadow_light_dir, float radius, float length)
 {
  ScopeProfiler sp(g_profiler, "CM::updateDrawListShadow()", SPT_AVG);
 
- const v3f camera_position = shadow_light_pos;
- const v3f camera_direction = shadow_light_dir;
- // I "fake" fov just to avoid creating a new function to handle orthographic
- // projection.
- const f32 camera_fov = m_camera_fov * 1.9f;
-
- v3s16 cam_pos_nodes = floatToInt(camera_position, BS);
+ v3s16 cam_pos_nodes = floatToInt(shadow_light_pos, BS);
  v3s16 p_blocks_min;
  v3s16 p_blocks_max;
- getBlocksInViewRange(cam_pos_nodes, &p_blocks_min, &p_blocks_max, shadow_range);
+ getBlocksInViewRange(cam_pos_nodes, &p_blocks_min, &p_blocks_max, radius + length);
 
  std::vector<v2s16> blocks_in_range;
 
@@ -889,10 +883,10 @@ void ClientMap::updateDrawListShadow(const v3f &shadow_light_pos, const v3f &sha
  // they are not inside the light frustum and it creates glitches.
  // FIXME: This could be removed if we figure out why they are missing
  // from the light frustum.
- for (auto &i : m_drawlist) {
- i.second->refGrab();
- m_drawlist_shadow[i.first] = i.second;
- }
+ // for (auto &i : m_drawlist) {
+ //  i.second->refGrab();
+ //  m_drawlist_shadow[i.first] = i.second;
+ // }
 
  // Number of blocks currently loaded by the client
  u32 blocks_loaded = 0;
@@ -919,23 +913,13 @@ void ClientMap::updateDrawListShadow(const v3f &shadow_light_pos, const v3f &sha
  continue;
  }
 
- float range = shadow_range;
-
- float d = 0.0;
- if (!isBlockInSight(block->getPos(), camera_position,
- camera_direction, camera_fov, range, &d))
+ v3f block_pos = intToFloat(block->getPos() * MAP_BLOCKSIZE, BS);
+ v3f projection = shadow_light_pos + shadow_light_dir * shadow_light_dir.dotProduct(block_pos - shadow_light_pos);
+ if (projection.getDistanceFrom(block_pos) > radius)
  continue;
 
  blocks_in_range_with_mesh++;
 
- /*
- Occlusion culling
- */
- if (isBlockOccluded(block, cam_pos_nodes)) {
- blocks_occlusion_culled++;
- continue;
- }
-
  // This block is in range. Reset usage timer.
  block->resetUsageTimer();
 

src/client/clientmap.h

@@ -116,7 +116,7 @@ class ClientMap : public Map, public scene::ISceneNode
  void getBlocksInViewRange(v3s16 cam_pos_nodes,
  v3s16 *p_blocks_min, v3s16 *p_blocks_max, float range=-1.0f);
  void updateDrawList();
- void updateDrawListShadow(const v3f &shadow_light_pos, const v3f &shadow_light_dir, float shadow_range);
+ void updateDrawListShadow(v3f shadow_light_pos, v3f shadow_light_dir, float radius, float length);
  // Returns true if draw list needs updating before drawing the next frame.
  bool needsUpdateDrawList() { return m_needs_update_drawlist; }
  void renderMap(video::IVideoDriver* driver, s32 pass);