From 8ac9945afac6a2377e4b9e9d7377e33be8326507 Mon Sep 17 00:00:00 2001
From: Sam Hocevar <sam@hocevar.net>
Date: Mon, 14 Feb 2011 01:26:43 +0000
Subject: [PATCH] Shader tests. Disabled for now.

---
 src/scene.cpp | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/src/scene.cpp b/src/scene.cpp
index db51c0fe..13832bd8 100644
--- a/src/scene.cpp
+++ b/src/scene.cpp
@@ -13,6 +13,7 @@
 #endif
 
 #include <cstdlib>
+#include <cstdio>
 #include <cmath>
 
 #ifdef WIN32
@@ -28,6 +29,9 @@
 
 #include "core.h"
 
+#define ATTRIB_POSITION 42 /* arbitrary id */
+#define SHADER_CRAP 0
+
 struct Tile
 {
     uint32_t prio, code;
@@ -55,6 +59,10 @@ private:
     int ntiles;
     float angle;
 
+#if SHADER_CRAP
+    GLuint prog, sh1, sh2;
+    GLint uni_mvp, uni_color;
+#endif
     GLuint *bufs;
     int nbufs;
 
@@ -63,6 +71,25 @@ private:
 
 Scene *SceneData::scene = NULL;
 
+#if SHADER_CRAP
+static char const *vertexshader =
+    "attribute vec4 position;\n"
+    "uniform mat4 mvp;\n"
+    "\n"
+    "void main()\n"
+    "{\n"
+    "    gl_Position = mvp * position;\n"
+    "}\n";
+
+static char const *fragmentshader =
+    "uniform lowp vec4 color;\n"
+    "\n"
+    "void main()\n"
+    "{\n"
+    "    gl_FragColor = color;\n"
+    "}\n";
+#endif
+
 /*
  * Public Scene class
  */
@@ -76,12 +103,47 @@ Scene::Scene(float angle)
 
     data->bufs = 0;
     data->nbufs = 0;
+
+#if SHADER_CRAP
+    data->sh1 = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(data->sh1, 1, &vertexshader, NULL);
+    glCompileShader(data->sh1);
+
+    char buf[4096];
+    GLsizei dummy;
+    glGetShaderInfoLog(data->sh1, 4096, &dummy, buf);
+    fprintf(stderr, "sh1 %i: %s", data->sh1, buf);
+
+    data->sh2 = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(data->sh2, 1, &fragmentshader, NULL);
+    glCompileShader(data->sh2);
+
+    glGetShaderInfoLog(data->sh2, 4096, &dummy, buf);
+    fprintf(stderr, "sh2 %i: %s", data->sh2, buf);
+
+    data->prog = glCreateProgram();
+    glAttachShader(data->prog, data->sh1);
+    glAttachShader(data->prog, data->sh2);
+
+    glBindAttribLocation(data->prog, ATTRIB_POSITION, "position");
+    glLinkProgram(data->prog);
+
+    data->uni_mvp = glGetUniformLocation(data->prog, "mvp");
+    data->uni_color = glGetUniformLocation(data->prog, "color");
+#endif
 }
 
 Scene::~Scene()
 {
     /* FIXME: this must be done while the GL context is still active.
      * Change the architecture to make sure of that. */
+#if SHADER_CRAP
+    glDetachShader(data->prog, data->sh1);
+    glDetachShader(data->prog, data->sh2);
+    glDeleteShader(data->sh1);
+    glDeleteShader(data->sh2);
+    glDeleteProgram(data->prog);
+#endif
     glDeleteBuffers(data->nbufs, data->bufs);
     delete data;
 }
@@ -170,11 +232,22 @@ void Scene::Render() // XXX: rename to Blit()
 
         glEnableClientState(GL_VERTEX_ARRAY);
         glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+#if SHADER_CRAP
+        glUseProgram(data->prog);
+        float4x4 mvp = float4x4::identity();
+        mvp = mvp - mvp;
+        glUniformMatrix4fv(data->uni_mvp, 1, GL_FALSE, (GLfloat *)&mvp[0][0]);
+        glUniform4f(data->uni_color, 1.0f, 0.0f, 1.0f, 1.0f);
+#endif
 
         glBindBuffer(GL_ARRAY_BUFFER, data->bufs[buf]);
         glBufferData(GL_ARRAY_BUFFER, 6 * 3 * (n - i) * sizeof(float),
                      vertex, GL_DYNAMIC_DRAW);
         glVertexPointer(3, GL_FLOAT, 0, NULL);
+#if SHADER_CRAP
+        glVertexAttribPointer(ATTRIB_POSITION, (n - i) * 6, GL_FLOAT, false, 0, vertex);
+        glEnableVertexAttribArray(ATTRIB_POSITION);
+#endif
 
         glBindBuffer(GL_ARRAY_BUFFER, data->bufs[buf + 1]);
         glBufferData(GL_ARRAY_BUFFER, 6 * 2 * (n - i) * sizeof(float),