draw spinning quad with a texture instead of smoothed colors

assets/shaders/fragment.glsl

@@ -1,7 +1,8 @@
 
-varying vec3 color_i;
+varying vec2 tex_coord_i;
+uniform sampler2D tex;
 
 void main()
 {
-    gl_FragColor = vec4(color_i, 1);
+    gl_FragColor = texture2D(tex, tex_coord_i);
 }

assets/shaders/vertex.glsl

@@ -2,11 +2,11 @@
 uniform mat4 projection;
 uniform mat4 modelview;
 attribute vec3 pos;
-attribute vec3 color;
+attribute vec2 tex_coord;
-varying vec3 color_i;
+varying vec2 tex_coord_i;
 
 void main()
 {
     gl_Position = projection * modelview * vec4(pos, 1);
-    color_i = color;
+    tex_coord_i = tex_coord;
 }

src/com/homelinux/holtrop/opengltest/MainOpenGL.java

@@ -3,7 +3,6 @@ package com.homelinux.holtrop.opengltest;
 import android.opengl.GLSurfaceView;
 import android.app.Activity;
 import android.os.Bundle;
-import android.content.res.AssetManager;
 import android.view.WindowManager;
 import android.view.Window;
 
@@ -21,7 +20,7 @@ public class MainOpenGL extends Activity
         getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                 WindowManager.LayoutParams.FLAG_FULLSCREEN);
 
-        mGLView = new MyGLSurfaceView(this, getAssets());
+        mGLView = new MyGLSurfaceView(this, getAssets(), getResources());
         setContentView(mGLView);
     }
 }

src/com/homelinux/holtrop/opengltest/MyGLSurfaceView.java

@@ -3,19 +3,21 @@ package com.homelinux.holtrop.opengltest;
 import android.opengl.GLSurfaceView;
 import android.content.Context;
 import android.content.res.AssetManager;
+import android.content.res.Resources;
 import android.view.MotionEvent;
 
 public class MyGLSurfaceView extends GLSurfaceView
 {
     MyRenderer m_renderer;
 
-    public MyGLSurfaceView(Context context, AssetManager am)
+    public MyGLSurfaceView(Context context, AssetManager am,
+            Resources resources)
     {
         super(context);
 
         setEGLContextClientVersion(2);
 
-        m_renderer = new MyRenderer(am);
+        m_renderer = new MyRenderer(am, resources);
         setRenderer(m_renderer);
     }
 

src/com/homelinux/holtrop/opengltest/MyRenderer.java

@@ -10,6 +10,7 @@ import java.nio.IntBuffer;
 import java.nio.ByteOrder;
 import android.util.Log;
 import android.content.res.AssetManager;
+import android.content.res.Resources;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.BufferedReader;
@@ -17,6 +18,9 @@ import java.io.IOException;
 import android.opengl.Matrix;
 import android.os.SystemClock;
 import android.view.MotionEvent;
+import android.graphics.BitmapFactory;
+import android.graphics.Bitmap;
+import android.opengl.GLUtils;
 
 public class MyRenderer implements GLSurfaceView.Renderer
 {
@@ -24,6 +28,7 @@ public class MyRenderer implements GLSurfaceView.Renderer
     private final String DBGTAG = "JoshsOpenGL";
     private FloatBuffer m_quad_attrib_buffer;
     private AssetManager m_asset_manager;
+    private Resources m_resources;
     private float m_proj_matrix[] = new float[16];
     private float m_modelview[] = new float[16];
     private int m_width;
@@ -32,9 +37,10 @@ public class MyRenderer implements GLSurfaceView.Renderer
     private float m_x = 0.0f;
     private float m_y = 0.0f;
 
-    public MyRenderer(AssetManager am)
+    public MyRenderer(AssetManager am, Resources resources)
     {
         m_asset_manager = am;
+        m_resources = resources;
     }
 
     public void checkGLError(String glOperation)
@@ -87,10 +93,10 @@ public class MyRenderer implements GLSurfaceView.Renderer
     public void onSurfaceCreated(GL10 unused, EGLConfig config)
     {
         final float attribs[] = {
-            1, 1, 0,    1, 1, 1,
+            1, 1, 0,    1, 1,
-            -1, 1, 0,   1, 0, 0,
+            -1, 1, 0,   0, 1,
-            -1, -1, 0,  0, 1, 0,
+            -1, -1, 0,  0, 0,
-            1, -1, 0,   0, 0, 1
+            1, -1, 0,   1, 0,
         };
         checkGLError("onSurfaceCreated");
         ByteBuffer bb = ByteBuffer.allocateDirect(attribs.length * 4);
@@ -116,6 +122,24 @@ public class MyRenderer implements GLSurfaceView.Renderer
             Log.e(DBGTAG, "Program log: " + info_log);
         }
 
+        Bitmap texture = BitmapFactory.decodeResource(m_resources,
+                R.drawable.texture);
+        int[] textures = new int[1];
+        GLES20.glGenTextures(1, textures, 0);
+        checkGLError("glGenTextures");
+        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textures[0]);
+        checkGLError("glBindTexture");
+        GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D,
+                GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR_MIPMAP_LINEAR);
+        GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D,
+                GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);
+        checkGLError("glTexParameterf");
+        GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, texture, 0);
+        checkGLError("GLUtils.texImage2D");
+        GLES20.glGenerateMipmap(GLES20.GL_TEXTURE_2D);
+        checkGLError("glGenerateMipmap");
+        texture.recycle();
+
         GLES20.glClearColor(1.0f, 0.6f, 0.1f, 1.0f);
     }
 
@@ -133,21 +157,22 @@ public class MyRenderer implements GLSurfaceView.Renderer
                 GLES20.glGetUniformLocation(m_program, "modelview"),
                 1, false, m_modelview, 0);
         int attr_pos = GLES20.glGetAttribLocation(m_program, "pos");
-        int attr_color = GLES20.glGetAttribLocation(m_program, "color");
+        int attr_tex_coord = GLES20.glGetAttribLocation(m_program, "tex_coord");
+        checkGLError("glGetAttribLocation");
         GLES20.glEnableVertexAttribArray(attr_pos);
-        GLES20.glEnableVertexAttribArray(attr_color);
+        GLES20.glEnableVertexAttribArray(attr_tex_coord);
         checkGLError("glEnableVertexAttribArray");
         m_quad_attrib_buffer.position(0);
         GLES20.glVertexAttribPointer(attr_pos, 3, GLES20.GL_FLOAT, false,
-                6 * 4, m_quad_attrib_buffer);
+                5 * 4, m_quad_attrib_buffer);
         m_quad_attrib_buffer.position(3);
-        GLES20.glVertexAttribPointer(attr_color, 3, GLES20.GL_FLOAT, false,
+        GLES20.glVertexAttribPointer(attr_tex_coord, 2, GLES20.GL_FLOAT, false,
-                6 * 4, m_quad_attrib_buffer);
+                5 * 4, m_quad_attrib_buffer);
         checkGLError("glVertexAttribPointer");
         GLES20.glDrawArrays(GLES20.GL_TRIANGLE_FAN, 0, 4);
         checkGLError("glDrawArrays");
         GLES20.glDisableVertexAttribArray(attr_pos);
-        GLES20.glDisableVertexAttribArray(attr_color);
+        GLES20.glDisableVertexAttribArray(attr_tex_coord);
         checkGLError("glDisableVertexAttribArray");
     }