Surface shadow improvement

Not allowing bias go below 0.001 prevents the shadow acne. Faulty formula
for lighning direction.

Task-number: QTRD-3382
Change-Id: Ided8bf423a961744ace8bef32ae18d6fa2c443ef
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@theqtcompany.com>

7 files changed, 80 insertions, 13 deletions

diff --git a/src/datavisualization/engine/engine.qrc b/src/datavisualization/engine/engine.qrc
index 8c234a3b..0ef169c9 100644
--- a/src/datavisualization/engine/engine.qrc
+++ b/src/datavisualization/engine/engine.qrc
@@ -69,5 +69,6 @@
         <file alias="fragment3DSliceFrames">shaders/3dsliceframes.frag</file>
         <file alias="vertexPosition">shaders/position.vert</file>
         <file alias="fragmentPositionMap">shaders/positionmap.frag</file>
+        <file alias="fragmentTexturedSurfaceShadow">shaders/surfaceTexturedShadow.frag</file>
     </qresource>
 </RCC>
diff --git a/src/datavisualization/engine/shaders/surfaceShadowFlat.frag b/src/datavisualization/engine/shaders/surfaceShadowFlat.frag
index 4b0dfae0..7eaba7f5 100644
--- a/src/datavisualization/engine/shaders/surfaceShadowFlat.frag
+++ b/src/datavisualization/engine/shaders/surfaceShadowFlat.frag
@@ -2,7 +2,7 @@
 
 #extension GL_EXT_gpu_shader4 : require
 
-varying highp vec3 coords_mdl;
+varying highp vec2 coords_mdl;
 varying highp vec3 position_wrld;
 flat varying highp vec3 normal_cmr;
 varying highp vec3 eyeDirection_cmr;
@@ -51,7 +51,7 @@ void main() {
     highp float cosAlpha = clamp(dot(E, R), 0.0, 1.0);
 
     highp float bias = 0.005 * tan(acos(cosTheta));
-    bias = clamp(bias, 0.0, 0.01);
+    bias = clamp(bias, 0.001, 0.01);
 
     vec4 shadCoords = shadowCoord;
     shadCoords.z -= bias;
diff --git a/src/datavisualization/engine/shaders/surfaceShadowFlat.vert b/src/datavisualization/engine/shaders/surfaceShadowFlat.vert
index d80e062e..98fdde3f 100644
--- a/src/datavisualization/engine/shaders/surfaceShadowFlat.vert
+++ b/src/datavisualization/engine/shaders/surfaceShadowFlat.vert
@@ -2,10 +2,6 @@
 
 #extension GL_EXT_gpu_shader4 : require
 
-attribute highp vec3 vertexPosition_mdl;
-attribute highp vec3 vertexNormal_mdl;
-attribute highp vec2 vertexUV;
-
 uniform highp mat4 MVP;
 uniform highp mat4 V;
 uniform highp mat4 M;
@@ -13,13 +9,17 @@ uniform highp mat4 itM;
 uniform highp mat4 depthMVP;
 uniform highp vec3 lightPosition_wrld;
 
+attribute highp vec3 vertexPosition_mdl;
+attribute highp vec3 vertexNormal_mdl;
+attribute highp vec2 vertexUV;
+
 varying highp vec2 UV;
 varying highp vec3 position_wrld;
 flat varying highp vec3 normal_cmr;
 varying highp vec3 eyeDirection_cmr;
 varying highp vec3 lightDirection_cmr;
 varying highp vec4 shadowCoord;
-varying highp vec3 coords_mdl;
+varying highp vec2 coords_mdl;
 
 const highp mat4 bias = mat4(0.5, 0.0, 0.0, 0.0,
                              0.0, 0.5, 0.0, 0.0,
@@ -28,13 +28,12 @@ const highp mat4 bias = mat4(0.5, 0.0, 0.0, 0.0,
 
 void main() {
     gl_Position = MVP * vec4(vertexPosition_mdl, 1.0);
-    coords_mdl = vertexPosition_mdl;
+    coords_mdl = vertexPosition_mdl.xy;
     shadowCoord = bias * depthMVP * vec4(vertexPosition_mdl, 1.0);
     position_wrld = vec4(M * vec4(vertexPosition_mdl, 1.0)).xyz;
     vec3 vertexPosition_cmr = vec4(V * M * vec4(vertexPosition_mdl, 1.0)).xyz;
     eyeDirection_cmr = vec3(0.0, 0.0, 0.0) - vertexPosition_cmr;
-    vec3 lightPosition_cmr = vec4(V * vec4(lightPosition_wrld, 1.0)).xyz;
-    lightDirection_cmr = lightPosition_cmr + eyeDirection_cmr;
+    lightDirection_cmr = vec4(V * vec4(lightPosition_wrld, 0.0)).xyz;
     normal_cmr = vec4(V * itM * vec4(vertexNormal_mdl, 0.0)).xyz;
     UV = vertexUV;
 }
diff --git a/src/datavisualization/engine/shaders/surfaceShadowNoTex.frag b/src/datavisualization/engine/shaders/surfaceShadowNoTex.frag
index d6195227..985214be 100644
--- a/src/datavisualization/engine/shaders/surfaceShadowNoTex.frag
+++ b/src/datavisualization/engine/shaders/surfaceShadowNoTex.frag
@@ -49,7 +49,7 @@ void main() {
     highp float cosAlpha = clamp(dot(E, R), 0.0, 1.0);
 
     highp float bias = 0.005 * tan(acos(cosTheta));
-    bias = clamp(bias, 0.0, 0.01);
+    bias = clamp(bias, 0.001, 0.01);
 
     vec4 shadCoords = shadowCoord;
     shadCoords.z -= bias;
diff --git a/src/datavisualization/engine/shaders/surfaceTexturedShadow.frag b/src/datavisualization/engine/shaders/surfaceTexturedShadow.frag
new file mode 100644
index 00000000..a4259565
--- /dev/null
+++ b/src/datavisualization/engine/shaders/surfaceTexturedShadow.frag
@@ -0,0 +1,67 @@
+#version 120
+
+uniform highp float lightStrength;
+uniform highp float ambientStrength;
+uniform highp float shadowQuality;
+uniform highp sampler2D textureSampler;
+uniform highp sampler2DShadow shadowMap;
+uniform highp vec4 lightColor;
+
+varying highp vec4 shadowCoord;
+varying highp vec2 UV;
+varying highp vec3 position_wrld;
+varying highp vec3 normal_cmr;
+varying highp vec3 eyeDirection_cmr;
+varying highp vec3 lightDirection_cmr;
+
+highp vec2 poissonDisk[16] = vec2[16](vec2(-0.94201624, -0.39906216),
+                                      vec2(0.94558609, -0.76890725),
+                                      vec2(-0.094184101, -0.92938870),
+                                      vec2(0.34495938, 0.29387760),
+                                      vec2(-0.91588581, 0.45771432),
+                                      vec2(-0.81544232, -0.87912464),
+                                      vec2(-0.38277543, 0.27676845),
+                                      vec2(0.97484398, 0.75648379),
+                                      vec2(0.44323325, -0.97511554),
+                                      vec2(0.53742981, -0.47373420),
+                                      vec2(-0.26496911, -0.41893023),
+                                      vec2(0.79197514, 0.19090188),
+                                      vec2(-0.24188840, 0.99706507),
+                                      vec2(-0.81409955, 0.91437590),
+                                      vec2(0.19984126, 0.78641367),
+                                      vec2(0.14383161, -0.14100790));
+
+void main() {
+    highp vec3 materialDiffuseColor = texture2D(textureSampler, UV).rgb;
+    highp vec3 materialAmbientColor = lightColor.rgb * ambientStrength * materialDiffuseColor;
+    highp vec3 materialSpecularColor = lightColor.rgb * 0.2;
+
+    highp vec3 n = normalize(normal_cmr);
+    highp vec3 l = normalize(lightDirection_cmr);
+    highp float cosTheta = clamp(dot(n, l), 0.0, 1.0);
+
+    highp vec3 E = normalize(eyeDirection_cmr);
+    highp vec3 R = reflect(-l, n);
+    highp float cosAlpha = clamp(dot(E, R), 0.0, 1.0);
+
+    highp float bias = 0.005 * tan(acos(cosTheta));
+    bias = clamp(bias, 0.001, 0.01);
+
+    vec4 shadCoords = shadowCoord;
+    shadCoords.z -= bias;
+
+    highp float visibility = 0.6;
+    for (int i = 0; i < 15; i++) {
+        vec4 shadCoordsPD = shadCoords;
+        shadCoordsPD.x += cos(poissonDisk[i].x) / shadowQuality;
+        shadCoordsPD.y += sin(poissonDisk[i].y) / shadowQuality;
+        visibility += 0.025 * shadow2DProj(shadowMap, shadCoordsPD).r;
+    }
+
+    gl_FragColor.rgb =
+        (materialAmbientColor +
+        materialDiffuseColor * lightStrength * cosTheta +
+        materialSpecularColor * lightStrength * pow(cosAlpha, 10));
+    gl_FragColor.a = texture2D(textureSampler, UV).a;
+    gl_FragColor.rgb = visibility * clamp(gl_FragColor.rgb, 0.0, 1.0);
+}
diff --git a/src/datavisualization/engine/shaders/surfaceTexturedShadowFlat.frag b/src/datavisualization/engine/shaders/surfaceTexturedShadowFlat.frag
index 421fe342..496f4777 100644
--- a/src/datavisualization/engine/shaders/surfaceTexturedShadowFlat.frag
+++ b/src/datavisualization/engine/shaders/surfaceTexturedShadowFlat.frag
@@ -49,7 +49,7 @@ void main() {
     highp float cosAlpha = clamp(dot(E, R), 0.0, 1.0);
 
     highp float bias = 0.005 * tan(acos(cosTheta));
-    bias = clamp(bias, 0.0, 0.01);
+    bias = clamp(bias, 0.001, 0.01);
 
     vec4 shadCoords = shadowCoord;
     shadCoords.z -= bias;
diff --git a/src/datavisualization/engine/surface3drenderer.cpp b/src/datavisualization/engine/surface3drenderer.cpp
index e39c986c..743c6fe0 100644
--- a/src/datavisualization/engine/surface3drenderer.cpp
+++ b/src/datavisualization/engine/surface3drenderer.cpp
@@ -2886,7 +2886,7 @@ void Surface3DRenderer::initShaders(const QString &vertexShader, const QString &
         m_surfaceSmoothShader = new ShaderHelper(this, QStringLiteral(":/shaders/vertexShadow"),
                                                  QStringLiteral(":/shaders/fragmentSurfaceShadowNoTex"));
         m_surfaceTexturedSmoothShader = new ShaderHelper(this, QStringLiteral(":/shaders/vertexShadow"),
-                                                         QStringLiteral(":/shaders/fragmentShadow"));
+                                                         QStringLiteral(":/shaders/fragmentTexturedSurfaceShadow"));
     } else {
         m_surfaceSmoothShader = new ShaderHelper(this, QStringLiteral(":/shaders/vertex"),
                                                  QStringLiteral(":/shaders/fragmentSurface"));