Make shadow mapping functional on ES 3

To preserve our sanity we will only support ES 3.x, not 2.0 + GL_OES_depth_texture
+ EXT_shadow_samplers. This way we can provide version 300 es shaders and do not
have to introduce yet another filter and technique.

Change-Id: Ib5c826d6540b4848f0cb4629e5311150169a9697
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

6 files changed, 292 insertions, 0 deletions

diff --git a/examples/shadow-map-qml/AdsEffect.qml b/examples/shadow-map-qml/AdsEffect.qml
index 7df656168..1ddc58f3b 100644
--- a/examples/shadow-map-qml/AdsEffect.qml
+++ b/examples/shadow-map-qml/AdsEffect.qml
@@ -105,6 +105,44 @@ Effect {
                     // no special render state set => use the default set of states
                 }
             ]
+        },
+        Technique {
+            openGLFilter {
+                api: OpenGLFilter.ES
+                majorVersion: 3
+                minorVersion: 0
+            }
+
+            renderPasses: [
+                RenderPass {
+                    annotations: [ Annotation { name: "pass"; value: "shadowmap" } ]
+
+                    shaderProgram: ShaderProgram {
+                        vertexShaderCode:   loadSource("qrc:/shaders/es3/shadowmap.vert")
+                        fragmentShaderCode: loadSource("qrc:/shaders/es3/shadowmap.frag")
+                    }
+
+                    renderStates: [
+                        PolygonOffset { factor: 4; units: 4 },
+                        DepthTest { func: DepthTest.Less }
+                    ]
+                },
+
+                RenderPass {
+                    annotations: [ Annotation { name : "pass"; value : "forward" } ]
+
+                    bindings: [
+                        ParameterMapping { parameterName: "ambient";  shaderVariableName: "ka"; bindingType: ParameterMapping.Uniform },
+                        ParameterMapping { parameterName: "diffuse";  shaderVariableName: "kd"; bindingType: ParameterMapping.Uniform },
+                        ParameterMapping { parameterName: "specular"; shaderVariableName: "ks"; bindingType: ParameterMapping.Uniform }
+                    ]
+
+                    shaderProgram: ShaderProgram {
+                        vertexShaderCode:   loadSource("qrc:/shaders/es3/ads.vert")
+                        fragmentShaderCode: loadSource("qrc:/shaders/es3/ads.frag")
+                    }
+                }
+            ]
         }
     ]
 }
diff --git a/examples/shadow-map-qml/shaders/es3/ads.frag b/examples/shadow-map-qml/shaders/es3/ads.frag
new file mode 100644
index 000000000..30977cf1e
--- /dev/null
+++ b/examples/shadow-map-qml/shaders/es3/ads.frag
@@ -0,0 +1,95 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#version 300 es
+
+precision highp float;
+
+uniform mat4 viewMatrix;
+
+uniform vec3 lightPosition;
+uniform vec3 lightIntensity;
+
+uniform vec3 ka;            // Ambient reflectivity
+uniform vec3 kd;            // Diffuse reflectivity
+uniform vec3 ks;            // Specular reflectivity
+uniform float shininess;    // Specular shininess factor
+
+uniform sampler2DShadow shadowMapTexture;
+
+in vec4 positionInLightSpace;
+
+in vec3 position;
+in vec3 normal;
+
+out vec4 fragColor;
+
+vec3 dsModel(const in vec3 pos, const in vec3 n)
+{
+    // Calculate the vector from the light to the fragment
+    vec3 s = normalize(vec3(viewMatrix * vec4(lightPosition, 1.0)) - pos);
+
+    // Calculate the vector from the fragment to the eye position
+    // (origin since this is in "eye" or "camera" space)
+    vec3 v = normalize(-pos);
+
+    // Reflect the light beam using the normal at this fragment
+    vec3 r = reflect(-s, n);
+
+    // Calculate the diffuse component
+    float diffuse = max(dot(s, n), 0.0);
+
+    // Calculate the specular component
+    float specular = 0.0;
+    if (dot(s, n) > 0.0)
+        specular = pow(max(dot(r, v), 0.0), shininess);
+
+    // Combine the diffuse and specular contributions (ambient is taken into account by the caller)
+    return lightIntensity * (kd * diffuse + ks * specular);
+}
+
+void main()
+{
+    float shadowMapSample = textureProj(shadowMapTexture, positionInLightSpace);
+
+    vec3 ambient = lightIntensity * ka;
+
+    vec3 result = ambient;
+    if (shadowMapSample > 0.0)
+        result += dsModel(position, normalize(normal));
+
+    fragColor = vec4(result, 1.0);
+}
diff --git a/examples/shadow-map-qml/shaders/es3/ads.vert b/examples/shadow-map-qml/shaders/es3/ads.vert
new file mode 100644
index 000000000..c304fbaad
--- /dev/null
+++ b/examples/shadow-map-qml/shaders/es3/ads.vert
@@ -0,0 +1,66 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#version 300 es
+
+in vec3 vertexPosition;
+in vec3 vertexNormal;
+
+out vec4 positionInLightSpace;
+out vec3 position;
+out vec3 normal;
+
+uniform mat4 lightViewProjection;
+uniform mat4 modelMatrix;
+uniform mat4 modelView;
+uniform mat3 modelViewNormal;
+uniform mat4 mvp;
+
+void main()
+{
+    // positionInLightSpace = lightViewProjection * modelMatrix * vec4(vertexPosition, 1.0);
+    const mat4 shadowMatrix = mat4(0.5, 0.0, 0.0, 0.0,
+                                   0.0, 0.5, 0.0, 0.0,
+                                   0.0, 0.0, 0.5, 0.0,
+                                   0.5, 0.5, 0.5, 1.0);
+
+    positionInLightSpace = shadowMatrix * lightViewProjection * modelMatrix * vec4(vertexPosition, 1.0);
+
+    normal = normalize(modelViewNormal * vertexNormal);
+    position = vec3(modelView * vec4(vertexPosition, 1.0));
+
+    gl_Position = mvp * vec4(vertexPosition, 1.0);
+}
diff --git a/examples/shadow-map-qml/shaders/es3/shadowmap.frag b/examples/shadow-map-qml/shaders/es3/shadowmap.frag
new file mode 100644
index 000000000..22fe0431b
--- /dev/null
+++ b/examples/shadow-map-qml/shaders/es3/shadowmap.frag
@@ -0,0 +1,43 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#version 300 es
+
+precision highp float;
+
+void main()
+{
+}
diff --git a/examples/shadow-map-qml/shaders/es3/shadowmap.vert b/examples/shadow-map-qml/shaders/es3/shadowmap.vert
new file mode 100644
index 000000000..1fe6b3724
--- /dev/null
+++ b/examples/shadow-map-qml/shaders/es3/shadowmap.vert
@@ -0,0 +1,46 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#version 300 es
+
+in vec3 vertexPosition;
+
+uniform mat4 mvp;
+
+void main()
+{
+    gl_Position = mvp * vec4(vertexPosition, 1.0);
+}
diff --git a/examples/shadow-map-qml/shadow-map-qml.qrc b/examples/shadow-map-qml/shadow-map-qml.qrc
index 821f84483..9aa6e2c73 100644
--- a/examples/shadow-map-qml/shadow-map-qml.qrc
+++ b/examples/shadow-map-qml/shadow-map-qml.qrc
@@ -14,6 +14,10 @@
         <file>shaders/ads.vert</file>
         <file>shaders/shadowmap.frag</file>
         <file>shaders/shadowmap.vert</file>
+        <file>shaders/es3/ads.frag</file>
+        <file>shaders/es3/ads.vert</file>
+        <file>shaders/es3/shadowmap.frag</file>
+        <file>shaders/es3/shadowmap.vert</file>
     </qresource>
 </RCC>