Interactive shadows (#14702)

Co-authored-by: Ian Bassi <12130714+ianalexis@users.noreply.github.com>
Co-authored-by: Ian Bassi <ian.bassi@outlook.com>

resources/shaders/110/gouraud.fs

@@ -50,6 +50,15 @@ uniform PrintVolumeDetection print_volume;
 uniform float z_far;
 uniform float z_near;
 
+// Depth-based shadow map (object-on-object and self shadows). shadow_intensity == 0 disables it.
+uniform sampler2D shadow_map;
+uniform mat4 shadow_light_vp;
+uniform float shadow_intensity;
+uniform float shadow_map_texel;
+
+// LIGHT_TOP_DIR in eye space (matches the diffuse light used for shading in gouraud.vs).
+const vec3 SHADOW_LIGHT_DIR = vec3(-0.4574957, 0.4574957, 0.7624929);
+
 varying vec3 clipping_planes_dots;
 varying float color_clip_plane_dot;
 
@@ -125,6 +134,35 @@ float DetectSilho(vec2 fragCoord)
         );
 }
 
+// Returns a lighting multiplier in [1 - shadow_intensity, 1]: < 1 where the fragment is
+// occluded from the light in the shadow map. 3x3 PCF softens the edges.
+float shadow_shade()
+{
+    if (shadow_intensity <= 0.0)
+        return 1.0;
+
+    vec4 lp = shadow_light_vp * world_pos;
+    vec3 proj = lp.xyz / lp.w;
+    proj = proj * 0.5 + 0.5;
+    if (proj.z > 1.0)
+        return 1.0;
+
+    // Slope-scaled depth bias: larger where the surface grazes / faces away from the light. This
+    // suppresses self-shadow acne without discarding real shadows cast by other objects onto
+    // back-facing surfaces (e.g. the shaded back/tip of a cone sitting inside a larger shadow).
+    float NdotL = dot(normalize(eye_normal), SHADOW_LIGHT_DIR);
+    float bias = mix(0.0004, 0.004, clamp(1.0 - NdotL, 0.0, 1.0));
+    // 5x5 PCF: softens shadow edges into a smooth penumbra and blurs residual facet acne.
+    float sum = 0.0;
+    for (int x = -2; x <= 2; ++x) {
+        for (int y = -2; y <= 2; ++y) {
+            float closest = texture2D(shadow_map, proj.xy + vec2(float(x), float(y)) * shadow_map_texel).r;
+            sum += (proj.z - bias > closest) ? 1.0 : 0.0;
+        }
+    }
+    return 1.0 - shadow_intensity * (sum / 25.0);
+}
+
 void main()
 {
     if (any(lessThan(clipping_planes_dots, ZERO)))
@@ -166,9 +204,11 @@ void main()
 	}
 	color.rgb = (any(lessThan(pv_check_min, ZERO)) || any(greaterThan(pv_check_max, ZERO))) ? mix(color.rgb, ZERO, 0.3333) : color.rgb;
 
+    float shade = shadow_shade();
+
     //BBS: add outline_color
     if (is_outline) {
-        color = vec4(vec3(intensity.y) + color.rgb * intensity.x, color.a);
+        color = vec4((vec3(intensity.y) + color.rgb * intensity.x) * shade, color.a);
         vec2 fragCoord = gl_FragCoord.xy;
         float s = DetectSilho(fragCoord);
         // Makes silhouettes thicker.
@@ -176,13 +216,13 @@ void main()
         {
            s = max(s, DetectSilho(fragCoord.xy + vec2(i, 0)));
            s = max(s, DetectSilho(fragCoord.xy + vec2(0, i)));
-        }   
+        }
         gl_FragColor = vec4(mix(color.rgb, getBackfaceColor(color.rgb), s), color.a);
     }
 #ifdef ENABLE_ENVIRONMENT_MAP
     else if (use_environment_tex)
-        gl_FragColor = vec4(0.45 * texture(environment_tex, normalize(eye_normal).xy * 0.5 + 0.5).xyz + 0.8 * color.rgb * intensity.x, color.a);
+        gl_FragColor = vec4((0.45 * texture(environment_tex, normalize(eye_normal).xy * 0.5 + 0.5).xyz + 0.8 * color.rgb * intensity.x) * shade, color.a);
 #endif
     else
-        gl_FragColor = vec4(vec3(intensity.y) + color.rgb * intensity.x, color.a);
+        gl_FragColor = vec4((vec3(intensity.y) + color.rgb * intensity.x) * shade, color.a);
 }

resources/shaders/110/phong.fs

@@ -65,6 +65,12 @@ uniform float z_far;
 uniform float z_near;
 uniform bool enable_ssao;
 
+// Depth-based shadow map (object-on-object and self shadows). shadow_intensity == 0 disables it.
+uniform sampler2D shadow_map;
+uniform mat4 shadow_light_vp;
+uniform float shadow_intensity;
+uniform float shadow_map_texel;
+
 varying vec3 clipping_planes_dots;
 varying float color_clip_plane_dot;
 
@@ -167,10 +173,39 @@ vec3 compute_window_reflection(vec3 normal, vec3 view_dir)
     
     float intensity = window_light * bars * (0.15 + 0.15 * fresnel) * facing;
     intensity = clamp(intensity, 0.0, 0.25);
-    
+
     return vec3(intensity);
 }
 
+// Returns a lighting multiplier in [1 - shadow_intensity, 1]: < 1 where the fragment is
+// occluded from the light in the shadow map. 3x3 PCF softens the edges.
+float shadow_shade()
+{
+    if (shadow_intensity <= 0.0)
+        return 1.0;
+
+    vec4 lp = shadow_light_vp * world_pos;
+    vec3 proj = lp.xyz / lp.w;
+    proj = proj * 0.5 + 0.5;
+    if (proj.z > 1.0)
+        return 1.0;
+
+    // Slope-scaled depth bias: larger where the surface grazes / faces away from the light. This
+    // suppresses self-shadow acne without discarding real shadows cast by other objects onto
+    // back-facing surfaces (e.g. the shaded back/tip of a cone sitting inside a larger shadow).
+    float NdotL = dot(normalize(eye_normal), LIGHT_TOP_DIR);
+    float bias = mix(0.0004, 0.004, clamp(1.0 - NdotL, 0.0, 1.0));
+    // 5x5 PCF: softens shadow edges into a smooth penumbra and blurs residual facet acne.
+    float sum = 0.0;
+    for (int x = -2; x <= 2; ++x) {
+        for (int y = -2; y <= 2; ++y) {
+            float closest = texture2D(shadow_map, proj.xy + vec2(float(x), float(y)) * shadow_map_texel).r;
+            sum += (proj.z - bias > closest) ? 1.0 : 0.0;
+        }
+    }
+    return 1.0 - shadow_intensity * (sum / 25.0);
+}
+
 void main()
 {
     if (any(lessThan(clipping_planes_dots, ZERO)))
@@ -226,8 +261,10 @@ void main()
 
     // SSAO is applied in post-process pass. Keep base lighting unchanged here.
 
+    float shade = shadow_shade();
+
     if (is_outline) {
-        vec3 shaded_rgb = (vec3(specular) + window_reflection + color.rgb * diffuse) * PHONG_BRIGHTNESS;
+        vec3 shaded_rgb = (vec3(specular) + window_reflection + color.rgb * diffuse) * PHONG_BRIGHTNESS * shade;
         vec4 shaded_color = vec4(clamp(shaded_rgb, vec3(0.0), vec3(1.0)), color.a);
         vec2 fragCoord = gl_FragCoord.xy;
         float s = DetectSilho(fragCoord);
@@ -240,8 +277,8 @@ void main()
     }
 #ifdef ENABLE_ENVIRONMENT_MAP
     else if (use_environment_tex)
-        gl_FragColor = vec4(clamp((0.45 * texture2D(environment_tex, normalize(eye_normal).xy * 0.5 + 0.5).xyz + window_reflection + 0.8 * color.rgb * diffuse) * PHONG_BRIGHTNESS, vec3(0.0), vec3(1.0)), color.a);
+        gl_FragColor = vec4(clamp((0.45 * texture2D(environment_tex, normalize(eye_normal).xy * 0.5 + 0.5).xyz + window_reflection + 0.8 * color.rgb * diffuse) * PHONG_BRIGHTNESS * shade, vec3(0.0), vec3(1.0)), color.a);
 #endif
     else
-        gl_FragColor = vec4(clamp((vec3(specular) + window_reflection + color.rgb * diffuse) * PHONG_BRIGHTNESS, vec3(0.0), vec3(1.0)), color.a);
+        gl_FragColor = vec4(clamp((vec3(specular) + window_reflection + color.rgb * diffuse) * PHONG_BRIGHTNESS * shade, vec3(0.0), vec3(1.0)), color.a);
 }

resources/shaders/110/printbed_shadow.fs

@@ -0,0 +1,40 @@
+#version 110
+
+// Draws the build-plate as a receiver of the same depth shadow map used for object/self shadows,
+// so the plate, objects, and self-shadows all come from one unified technique.
+uniform sampler2D shadow_map;
+uniform mat4 shadow_light_vp;
+uniform float shadow_intensity;
+uniform float shadow_map_texel;
+
+varying vec4 world_pos;
+
+// Fraction of the 5x5 PCF kernel occluded from the light. Matches the object shadow shader.
+float shadow_occlusion()
+{
+    vec4 lp = shadow_light_vp * world_pos;
+    vec3 proj = lp.xyz / lp.w;
+    proj = proj * 0.5 + 0.5;
+    if (proj.z > 1.0)
+        return 0.0;
+
+    // The plate is a pure receiver (never rendered into the shadow map), so a tiny constant
+    // bias for numerical safety is enough here.
+    float bias = 0.0004;
+    float sum = 0.0;
+    for (int x = -2; x <= 2; ++x) {
+        for (int y = -2; y <= 2; ++y) {
+            float closest = texture2D(shadow_map, proj.xy + vec2(float(x), float(y)) * shadow_map_texel).r;
+            sum += (proj.z - bias > closest) ? 1.0 : 0.0;
+        }
+    }
+    return sum / 25.0;
+}
+
+void main()
+{
+    float occ = shadow_occlusion();
+    if (occ <= 0.0)
+        discard;
+    gl_FragColor = vec4(0.0, 0.0, 0.0, shadow_intensity * occ);
+}

resources/shaders/110/printbed_shadow.vs

@@ -0,0 +1,16 @@
+#version 110
+
+uniform mat4 view_model_matrix;
+uniform mat4 projection_matrix;
+
+attribute vec3 v_position;
+
+// The plate mask quad is authored directly in world coordinates (z = 0 plane),
+// so v_position is already the world position of the fragment.
+varying vec4 world_pos;
+
+void main()
+{
+    world_pos = vec4(v_position, 1.0);
+    gl_Position = projection_matrix * view_model_matrix * vec4(v_position, 1.0);
+}

resources/shaders/140/gouraud.fs

@@ -49,6 +49,15 @@ uniform PrintVolumeDetection print_volume;
 uniform float z_far;
 uniform float z_near;
 
+// Depth-based shadow map (object-on-object and self shadows). shadow_intensity == 0 disables it.
+uniform sampler2D shadow_map;
+uniform mat4 shadow_light_vp;
+uniform float shadow_intensity;
+uniform float shadow_map_texel;
+
+// LIGHT_TOP_DIR in eye space (matches the diffuse light used for shading in gouraud.vs).
+const vec3 SHADOW_LIGHT_DIR = vec3(-0.4574957, 0.4574957, 0.7624929);
+
 in vec3 clipping_planes_dots;
 in float color_clip_plane_dot;
 
@@ -124,6 +133,35 @@ float DetectSilho(vec2 fragCoord)
         );
 }
 
+// Returns a lighting multiplier in [1 - shadow_intensity, 1]: < 1 where the fragment is
+// occluded from the light in the shadow map. 3x3 PCF softens the edges.
+float shadow_shade()
+{
+    if (shadow_intensity <= 0.0)
+        return 1.0;
+
+    vec4 lp = shadow_light_vp * world_pos;
+    vec3 proj = lp.xyz / lp.w;
+    proj = proj * 0.5 + 0.5;
+    if (proj.z > 1.0)
+        return 1.0;
+
+    // Slope-scaled depth bias: larger where the surface grazes / faces away from the light. This
+    // suppresses self-shadow acne without discarding real shadows cast by other objects onto
+    // back-facing surfaces (e.g. the shaded back/tip of a cone sitting inside a larger shadow).
+    float NdotL = dot(normalize(eye_normal), SHADOW_LIGHT_DIR);
+    float bias = mix(0.0004, 0.004, clamp(1.0 - NdotL, 0.0, 1.0));
+    // 5x5 PCF: softens shadow edges into a smooth penumbra and blurs residual facet acne.
+    float sum = 0.0;
+    for (int x = -2; x <= 2; ++x) {
+        for (int y = -2; y <= 2; ++y) {
+            float closest = texture(shadow_map, proj.xy + vec2(float(x), float(y)) * shadow_map_texel).r;
+            sum += (proj.z - bias > closest) ? 1.0 : 0.0;
+        }
+    }
+    return 1.0 - shadow_intensity * (sum / 25.0);
+}
+
 out vec4 out_color;
 
 void main()
@@ -167,9 +205,11 @@ void main()
 	}
 	color.rgb = (any(lessThan(pv_check_min, ZERO)) || any(greaterThan(pv_check_max, ZERO))) ? mix(color.rgb, ZERO, 0.3333) : color.rgb;
 
+    float shade = shadow_shade();
+
     //BBS: add outline_color
     if (is_outline) {
-        color = vec4(vec3(intensity.y) + color.rgb * intensity.x, color.a);
+        color = vec4((vec3(intensity.y) + color.rgb * intensity.x) * shade, color.a);
         vec2 fragCoord = gl_FragCoord.xy;
         float s = DetectSilho(fragCoord);
         // Makes silhouettes thicker.
@@ -177,13 +217,13 @@ void main()
         {
            s = max(s, DetectSilho(fragCoord.xy + vec2(i, 0)));
            s = max(s, DetectSilho(fragCoord.xy + vec2(0, i)));
-        }   
+        }
         out_color = vec4(mix(color.rgb, getBackfaceColor(color.rgb), s), color.a);
     }
 #ifdef ENABLE_ENVIRONMENT_MAP
     else if (use_environment_tex)
-        out_color = vec4(0.45 * texture(environment_tex, normalize(eye_normal).xy * 0.5 + 0.5).xyz + 0.8 * color.rgb * intensity.x, color.a);
+        out_color = vec4((0.45 * texture(environment_tex, normalize(eye_normal).xy * 0.5 + 0.5).xyz + 0.8 * color.rgb * intensity.x) * shade, color.a);
 #endif
     else
-        out_color = vec4(vec3(intensity.y) + color.rgb * intensity.x, color.a);
+        out_color = vec4((vec3(intensity.y) + color.rgb * intensity.x) * shade, color.a);
 }

resources/shaders/140/phong.fs

@@ -65,6 +65,12 @@ uniform float z_far;
 uniform float z_near;
 uniform bool enable_ssao;
 
+// Depth-based shadow map (object-on-object and self shadows). shadow_intensity == 0 disables it.
+uniform sampler2D shadow_map;
+uniform mat4 shadow_light_vp;
+uniform float shadow_intensity;
+uniform float shadow_map_texel;
+
 in vec3 clipping_planes_dots;
 in float color_clip_plane_dot;
 
@@ -170,11 +176,40 @@ vec3 compute_window_reflection(vec3 normal, vec3 view_dir)
     
 
     float intensity = window_light * bars * (0.15 + 0.15 * fresnel) * facing;
-    intensity = clamp(intensity, 0.0, 0.25);  
-    
+    intensity = clamp(intensity, 0.0, 0.25);
+
     return vec3(intensity);
 }
 
+// Returns a lighting multiplier in [1 - shadow_intensity, 1]: < 1 where the fragment is
+// occluded from the light in the shadow map. 3x3 PCF softens the edges.
+float shadow_shade()
+{
+    if (shadow_intensity <= 0.0)
+        return 1.0;
+
+    vec4 lp = shadow_light_vp * world_pos;
+    vec3 proj = lp.xyz / lp.w;
+    proj = proj * 0.5 + 0.5;
+    if (proj.z > 1.0)
+        return 1.0;
+
+    // Slope-scaled depth bias: larger where the surface grazes / faces away from the light. This
+    // suppresses self-shadow acne without discarding real shadows cast by other objects onto
+    // back-facing surfaces (e.g. the shaded back/tip of a cone sitting inside a larger shadow).
+    float NdotL = dot(normalize(eye_normal), LIGHT_TOP_DIR);
+    float bias = mix(0.0004, 0.004, clamp(1.0 - NdotL, 0.0, 1.0));
+    // 5x5 PCF: softens shadow edges into a smooth penumbra and blurs residual facet acne.
+    float sum = 0.0;
+    for (int x = -2; x <= 2; ++x) {
+        for (int y = -2; y <= 2; ++y) {
+            float closest = texture(shadow_map, proj.xy + vec2(float(x), float(y)) * shadow_map_texel).r;
+            sum += (proj.z - bias > closest) ? 1.0 : 0.0;
+        }
+    }
+    return 1.0 - shadow_intensity * (sum / 25.0);
+}
+
 void main()
 {
     if (any(lessThan(clipping_planes_dots, ZERO)))
@@ -230,8 +265,10 @@ void main()
 
     // SSAO is applied in post-process pass. Keep base lighting unchanged here.
 
+    float shade = shadow_shade();
+
     if (is_outline) {
-        vec3 shaded_rgb = (vec3(specular) + window_reflection + color.rgb * diffuse) * PHONG_BRIGHTNESS;
+        vec3 shaded_rgb = (vec3(specular) + window_reflection + color.rgb * diffuse) * PHONG_BRIGHTNESS * shade;
         vec4 shaded_color = vec4(clamp(shaded_rgb, vec3(0.0), vec3(1.0)), color.a);
         vec2 fragCoord = gl_FragCoord.xy;
         float s = DetectSilho(fragCoord);
@@ -244,8 +281,8 @@ void main()
     }
 #ifdef ENABLE_ENVIRONMENT_MAP
     else if (use_environment_tex)
-        out_color = vec4(clamp((0.45 * texture(environment_tex, normalize(eye_normal).xy * 0.5 + 0.5).xyz + window_reflection + 0.8 * color.rgb * diffuse) * PHONG_BRIGHTNESS, vec3(0.0), vec3(1.0)), color.a);
+        out_color = vec4(clamp((0.45 * texture(environment_tex, normalize(eye_normal).xy * 0.5 + 0.5).xyz + window_reflection + 0.8 * color.rgb * diffuse) * PHONG_BRIGHTNESS * shade, vec3(0.0), vec3(1.0)), color.a);
 #endif
     else
-        out_color = vec4(clamp((vec3(specular) + window_reflection + color.rgb * diffuse) * PHONG_BRIGHTNESS, vec3(0.0), vec3(1.0)), color.a);
+        out_color = vec4(clamp((vec3(specular) + window_reflection + color.rgb * diffuse) * PHONG_BRIGHTNESS * shade, vec3(0.0), vec3(1.0)), color.a);
 }

resources/shaders/140/printbed_shadow.fs

@@ -0,0 +1,42 @@
+#version 140
+
+// Draws the build-plate as a receiver of the same depth shadow map used for object/self shadows,
+// so the plate, objects, and self-shadows all come from one unified technique.
+uniform sampler2D shadow_map;
+uniform mat4 shadow_light_vp;
+uniform float shadow_intensity;
+uniform float shadow_map_texel;
+
+in vec4 world_pos;
+
+out vec4 out_color;
+
+// Fraction of the 5x5 PCF kernel occluded from the light. Matches the object shadow shader.
+float shadow_occlusion()
+{
+    vec4 lp = shadow_light_vp * world_pos;
+    vec3 proj = lp.xyz / lp.w;
+    proj = proj * 0.5 + 0.5;
+    if (proj.z > 1.0)
+        return 0.0;
+
+    // The plate is a pure receiver (never rendered into the shadow map), so a tiny constant
+    // bias for numerical safety is enough here.
+    float bias = 0.0004;
+    float sum = 0.0;
+    for (int x = -2; x <= 2; ++x) {
+        for (int y = -2; y <= 2; ++y) {
+            float closest = texture(shadow_map, proj.xy + vec2(float(x), float(y)) * shadow_map_texel).r;
+            sum += (proj.z - bias > closest) ? 1.0 : 0.0;
+        }
+    }
+    return sum / 25.0;
+}
+
+void main()
+{
+    float occ = shadow_occlusion();
+    if (occ <= 0.0)
+        discard;
+    out_color = vec4(0.0, 0.0, 0.0, shadow_intensity * occ);
+}

resources/shaders/140/printbed_shadow.vs

@@ -0,0 +1,16 @@
+#version 140
+
+uniform mat4 view_model_matrix;
+uniform mat4 projection_matrix;
+
+in vec3 v_position;
+
+// The plate mask quad is authored directly in world coordinates (z = 0 plane),
+// so v_position is already the world position of the fragment.
+out vec4 world_pos;
+
+void main()
+{
+    world_pos = vec4(v_position, 1.0);
+    gl_Position = projection_matrix * view_model_matrix * vec4(v_position, 1.0);
+}