glxsimple: Add a second frame drawing a solid color with GLSL.

This will allow us to test that we can trim out unused shaders.

diff --git a/cli/src/glxsimple.c b/cli/src/glxsimple.c
index 242fe94dc44169969d6aeac61332faa4d50e5b27..3c788c33ff132f0a4bea88e509d03028987ec88a 100644 (file)
--- a/cli/src/glxsimple.c
+++ b/cli/src/glxsimple.c
@@ -37,6 +37,66 @@
 int width = 64;
 int height = 64;
 
+static void
+paint_rgb_using_clear (double r, double g, double b)
+{
+        glClearColor(r, g, b, 1.0);
+        glClear(GL_COLOR_BUFFER_BIT);
+}
+
+static void
+paint_rgb_using_glsl (double r, double g, double b)
+{
+       const char * vs_source =
+               "void main()\n"
+               "{\n"
+               "        gl_Position = ftransform();\n"
+               "}\n";
+       const char * fs_source =
+               "#version 120\n"
+               "uniform vec4 color;\n"
+               "void main()\n"
+               "{\n"
+               "        gl_FragColor = color;\n"
+               "}\n";
+
+       GLuint vs, fs, program;
+       GLint color;
+
+       vs = glCreateShader (GL_VERTEX_SHADER);
+       glShaderSource (vs, 1, &vs_source, NULL);
+       glCompileShader (vs);
+
+       fs = glCreateShader (GL_FRAGMENT_SHADER);
+       glShaderSource (fs, 1, &fs_source, NULL);
+       glCompileShader (fs);
+
+       program = glCreateProgram ();
+       glAttachShader (program, vs);
+       glAttachShader (program, fs);
+
+       glLinkProgram (program);
+       glUseProgram (program);
+
+       color = glGetUniformLocation (program, "color");
+
+       glUniform4f (color, r, g, b, 1.0);
+
+       glMatrixMode (GL_PROJECTION);
+       glLoadIdentity ();
+       glOrtho (0, width, height, 0, 0, 1);
+       glMatrixMode (GL_MODELVIEW);
+
+       glBegin (GL_QUADS);
+       glVertex2f (0, 0);
+       glVertex2f (width, 0);
+       glVertex2f (width, height);
+       glVertex2f (0, height);
+       glEnd ();
+
+       glUseProgram (0);
+}
+
 static void
 draw (Display *dpy, Window window, int width, int height)
 {
@@ -54,6 +114,8 @@ draw (Display *dpy, Window window, int width, int height)
                 GLX_X_VISUAL_TYPE,     GLX_DIRECT_COLOR,
                 None
         };
+
+       /* Window and context setup. */
         XVisualInfo *visual_info = glXChooseVisual(dpy, 0, visual_attr);
         GLXContext ctx = glXCreateContext(dpy, visual_info, NULL, True);
         glXMakeCurrent(dpy, window, ctx);
@@ -67,11 +129,16 @@ draw (Display *dpy, Window window, int width, int height)
        }
 
         glViewport(0, 0, width, height);
-        glClearColor(1, 0, 1, 1);
-        glClear(GL_COLOR_BUFFER_BIT);
 
+       /* Frame 1: Draw a solid (magenta) frame using glClear. */
+       paint_rgb_using_clear (1, 0, 1);
+        glXSwapBuffers (dpy, window);
+
+       /* Frame 2: Draw a solid (yellow) frame using GLSL. */
+       paint_rgb_using_glsl (1, 1, 0);
         glXSwapBuffers (dpy, window);
 
+       /* Cleanup */
         glXDestroyContext (dpy, ctx);
 }