Add shadow mapping demo.

It uses a FBO with a depth-attachment ony.
The fragment shader samples the depth values from a sampler2D and uses
clip-space to NDC-space perspective divide together with a bias matrix
and a small depth offset to combat shadow acne.

res/demo/shadowMapping-fs.glsl

@@ -0,0 +1,9 @@
+/*
+ * Copyright LWJGL. All rights reserved.
+ * License terms: http://lwjgl.org/license.php
+ */
+#version 130
+
+void main(void) {
+	/* Nothing to do here... we are only rendering depth */
+}

res/demo/shadowMapping-vs.glsl

@@ -0,0 +1,13 @@
+/*
+ * Copyright LWJGL. All rights reserved.
+ * License terms: http://lwjgl.org/license.php
+ */
+#version 130
+
+uniform mat4 modelViewProjectionMatrix;
+
+in vec3 position;
+
+void main(void) {
+	gl_Position = modelViewProjectionMatrix * vec4(position, 1.0);
+}

res/demo/shadowMappingShade-fs.glsl

@@ -0,0 +1,38 @@
+/*
+ * Copyright LWJGL. All rights reserved.
+ * License terms: http://lwjgl.org/license.php
+ */
+#version 130
+
+#define DEPTH_OFFSET 0.00005
+#define LIGHT_INTENSITY 0.9
+#define SHADOW_INTENSITY 0.1
+
+uniform sampler2D depthTexture;
+uniform mat4 lightModelViewMatrix;
+uniform vec3 lightPosition;
+uniform vec3 lightLookAt;
+
+in vec4 lightBiasedClipPosition;
+in vec3 worldNormal;
+out vec4 color;
+
+void main(void) {
+	/* Convert the linearly interpolated clip-space position to NDC */
+    vec4 lightNDCPosition = lightBiasedClipPosition / lightBiasedClipPosition.w;
+
+    /* Sample the depth from the depth texture */
+    vec4 depth = texture2D(depthTexture, lightNDCPosition.xy);
+
+    /* Additionally, do standard lambertian/diffuse lighting */
+    float dot = max(0.0, dot(normalize(lightPosition - lightLookAt), worldNormal));
+
+	/* "in shadow" test... */
+    if (depth.z >= lightNDCPosition.z - DEPTH_OFFSET) {
+      /* lit */
+      color = vec4(LIGHT_INTENSITY, LIGHT_INTENSITY, LIGHT_INTENSITY, 1.0) * dot;
+    } else {
+      /* in shadow */
+      color = vec4(SHADOW_INTENSITY, SHADOW_INTENSITY, SHADOW_INTENSITY, 1.0);
+    }
+}

res/demo/shadowMappingShade-vs.glsl

@@ -0,0 +1,28 @@
+/*
+ * Copyright LWJGL. All rights reserved.
+ * License terms: http://lwjgl.org/license.php
+ */
+#version 130
+
+uniform mat4 modelViewProjectionMatrix;
+uniform mat4 lightModelViewProjectionMatrix;
+uniform mat4 biasMatrix;
+
+in vec3 position;
+in vec3 normal;
+out vec4 lightBiasedClipPosition;
+out vec3 worldNormal;
+
+void main(void) {
+	/* Pass the normal to the fragment shader (we do lighting computations in world coordinates) */
+    worldNormal = normal;
+
+    /* Compute vertex position as seen from
+       the light and use linear interpolation when passing it
+       to the fragment shader
+    */
+    lightBiasedClipPosition = biasMatrix * lightModelViewProjectionMatrix * vec4(position, 1.0);
+
+    /* Normally transform the vertex */
+	gl_Position = modelViewProjectionMatrix * vec4(position, 1.0);
+}

src/tests/org/lwjgl/demo/opengl/DemoUtils.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright LWJGL. All rights reserved.
+ * License terms: http://lwjgl.org/license.php
+ */
+package org.lwjgl.demo.opengl;
+
+import static org.lwjgl.demo.util.IOUtil.ioResourceToByteBuffer;
+import static org.lwjgl.opengl.GL20.GL_COMPILE_STATUS;
+import static org.lwjgl.opengl.GL20.glCompileShader;
+import static org.lwjgl.opengl.GL20.glCreateShader;
+import static org.lwjgl.opengl.GL20.glGetShaderInfoLog;
+import static org.lwjgl.opengl.GL20.glGetShaderi;
+import static org.lwjgl.opengl.GL20.glShaderSource;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
+
+import org.lwjgl.BufferUtils;
+import org.lwjgl.PointerBuffer;
+import org.lwjgl.demo.util.Vector3f;
+
+/**
+ * Utility methods for most of the ray tracing demos.
+ * 
+ * @author Kai Burjack
+ *
+ */
+public class DemoUtils {
+
+	/**
+	 * Write the vertices (position and normal) of an axis-aligned unit box into
+	 * the provided {@link FloatBuffer}.
+	 * 
+	 * @param fv
+	 *            the {@link FloatBuffer} receiving the vertex position and
+	 *            normal
+	 */
+	public static void triangulateUnitBox(FloatBuffer fv) {
+		triangulateBox(new Vector3f(-1.0f, -1.0f, -1.0f), new Vector3f(1.0f, 1.0f, 1.0f), fv);
+	}
+
+	/**
+	 * Write the vertices (position and normal) of an axis-aligned box with the
+	 * given corner coordinates into the provided {@link FloatBuffer}.
+	 * 
+	 * @param min
+	 *            the min corner
+	 * @param max
+	 *            the max corner
+	 * @param fv
+	 *            the {@link FloatBuffer} receiving the vertex position and
+	 *            normal
+	 */
+	public static void triangulateBox(Vector3f min, Vector3f max, FloatBuffer fv) {
+		/* Front face */
+		fv.put(min.x).put(min.y).put(max.z).put(0.0f).put(0.0f).put(1.0f);
+		fv.put(max.x).put(min.y).put(max.z).put(0.0f).put(0.0f).put(1.0f);
+		fv.put(max.x).put(max.y).put(max.z).put(0.0f).put(0.0f).put(1.0f);
+		fv.put(max.x).put(max.y).put(max.z).put(0.0f).put(0.0f).put(1.0f);
+		fv.put(min.x).put(max.y).put(max.z).put(0.0f).put(0.0f).put(1.0f);
+		fv.put(min.x).put(min.y).put(max.z).put(0.0f).put(0.0f).put(1.0f);
+		/* Back face */
+		fv.put(max.x).put(min.y).put(min.z).put(0.0f).put(0.0f).put(-1.0f);
+		fv.put(min.x).put(min.y).put(min.z).put(0.0f).put(0.0f).put(-1.0f);
+		fv.put(min.x).put(max.y).put(min.z).put(0.0f).put(0.0f).put(-1.0f);
+		fv.put(min.x).put(max.y).put(min.z).put(0.0f).put(0.0f).put(-1.0f);
+		fv.put(max.x).put(max.y).put(min.z).put(0.0f).put(0.0f).put(-1.0f);
+		fv.put(max.x).put(min.y).put(min.z).put(0.0f).put(0.0f).put(-1.0f);
+		/* Left face */
+		fv.put(min.x).put(min.y).put(min.z).put(-1.0f).put(0.0f).put(0.0f);
+		fv.put(min.x).put(min.y).put(max.z).put(-1.0f).put(0.0f).put(0.0f);
+		fv.put(min.x).put(max.y).put(max.z).put(-1.0f).put(0.0f).put(0.0f);
+		fv.put(min.x).put(max.y).put(max.z).put(-1.0f).put(0.0f).put(0.0f);
+		fv.put(min.x).put(max.y).put(min.z).put(-1.0f).put(0.0f).put(0.0f);
+		fv.put(min.x).put(min.y).put(min.z).put(-1.0f).put(0.0f).put(0.0f);
+		/* Right face */
+		fv.put(max.x).put(min.y).put(max.z).put(1.0f).put(0.0f).put(0.0f);
+		fv.put(max.x).put(min.y).put(min.z).put(1.0f).put(0.0f).put(0.0f);
+		fv.put(max.x).put(max.y).put(min.z).put(1.0f).put(0.0f).put(0.0f);
+		fv.put(max.x).put(max.y).put(min.z).put(1.0f).put(0.0f).put(0.0f);
+		fv.put(max.x).put(max.y).put(max.z).put(1.0f).put(0.0f).put(0.0f);
+		fv.put(max.x).put(min.y).put(max.z).put(1.0f).put(0.0f).put(0.0f);
+		/* Top face */
+		fv.put(min.x).put(max.y).put(max.z).put(0.0f).put(1.0f).put(0.0f);
+		fv.put(max.x).put(max.y).put(max.z).put(0.0f).put(1.0f).put(0.0f);
+		fv.put(max.x).put(max.y).put(min.z).put(0.0f).put(1.0f).put(0.0f);
+		fv.put(max.x).put(max.y).put(min.z).put(0.0f).put(1.0f).put(0.0f);
+		fv.put(min.x).put(max.y).put(min.z).put(0.0f).put(1.0f).put(0.0f);
+		fv.put(min.x).put(max.y).put(max.z).put(0.0f).put(1.0f).put(0.0f);
+		/* Bottom face */
+		fv.put(min.x).put(min.y).put(min.z).put(0.0f).put(-1.0f).put(0.0f);
+		fv.put(max.x).put(min.y).put(min.z).put(0.0f).put(-1.0f).put(0.0f);
+		fv.put(max.x).put(min.y).put(max.z).put(0.0f).put(-1.0f).put(0.0f);
+		fv.put(max.x).put(min.y).put(max.z).put(0.0f).put(-1.0f).put(0.0f);
+		fv.put(min.x).put(min.y).put(max.z).put(0.0f).put(-1.0f).put(0.0f);
+		fv.put(min.x).put(min.y).put(min.z).put(0.0f).put(-1.0f).put(0.0f);
+	}
+
+}