path: root/src/egl/stencil_test.c

//
// Book:      OpenGL(R) ES 2.0 Programming Guide
// Authors:   Aaftab Munshi, Dan Ginsburg, Dave Shreiner
// ISBN-10:   0321502795
// ISBN-13:   9780321502797
// Publisher: Addison-Wesley Professional
// URLs:      http://safari.informit.com/9780321563835
//            http://www.opengles-book.com
//

// Stencil_Test.c
//
//    This example shows various stencil buffer
//    operations.
//
#define HOOK

#include <stdlib.h>
#include "esUtil.h"

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdbool.h>
#include <EGL/egl.h>
#include <GLES2/gl2.h>
#include <dlfcn.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <stdarg.h>

#include "esTransform.h"
#include "eglutil.h"
#include "dump_gl_screen.h"
#include "viv_hook.h"

static EGLint const config_attribute_list[] = {
	EGL_RED_SIZE, 8,
	EGL_GREEN_SIZE, 8,
	EGL_BLUE_SIZE, 8,
	EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
	EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
	EGL_DEPTH_SIZE, 16,
	EGL_STENCIL_SIZE, 8,
	EGL_NONE
};

static EGLint const pbuffer_attribute_list[] = {
	EGL_WIDTH, 400,
	EGL_HEIGHT, 240,
	EGL_LARGEST_PBUFFER, EGL_TRUE,
    EGL_NONE
};

static const EGLint context_attribute_list[] = {
	EGL_CONTEXT_CLIENT_VERSION, 2,
	EGL_NONE
};

int main(int argc, char *argv[])
{
	EGLDisplay display;
	EGLint egl_major, egl_minor;
	EGLConfig config;
	EGLint num_config;
	EGLContext context;
	EGLSurface surface;
	GLuint vertex_shader;
	GLuint fragment_shader;
	GLuint program;
	GLint ret;
	GLint width, height;
#ifdef HOOK
        the_hook("/mnt/sdcard/egl2.fdr");
#endif

	const char *vertex_shader_source =
          "attribute vec4 a_position;   \n"
          "void main()                  \n"
          "{                            \n"
          "   gl_Position = a_position; \n"
          "}                            \n";

	const char *fragment_shader_source =
          "precision mediump float;  \n"
          "uniform vec4  u_color;    \n"
          "void main()               \n"
          "{                         \n"
          "  gl_FragColor = u_color; \n"
          "}                         \n";
   GLfloat vVertices[] = { 
       -0.75f,  0.25f,  0.50f, // Quad #0
       -0.25f,  0.25f,  0.50f,
       -0.25f,  0.75f,  0.50f,
       -0.75f,  0.75f,  0.50f,
	    0.25f,  0.25f,  0.90f, // Quad #1
		0.75f,  0.25f,  0.90f,
		0.75f,  0.75f,  0.90f,
		0.25f,  0.75f,  0.90f,
	   -0.75f, -0.75f,  0.50f, // Quad #2
       -0.25f, -0.75f,  0.50f,
       -0.25f, -0.25f,  0.50f,
       -0.75f, -0.25f,  0.50f,
        0.25f, -0.75f,  0.50f, // Quad #3
        0.75f, -0.75f,  0.50f,
        0.75f, -0.25f,  0.50f,
        0.25f, -0.25f,  0.50f,
       -1.00f, -1.00f,  0.00f, // Big Quad
        1.00f, -1.00f,  0.00f,
        1.00f,  1.00f,  0.00f,
       -1.00f,  1.00f,  0.00f
   };

   GLubyte indices[][6] = { 
       {  0,  1,  2,  0,  2,  3 }, // Quad #0
       {  4,  5,  6,  4,  6,  7 }, // Quad #1
       {  8,  9, 10,  8, 10, 11 }, // Quad #2
       { 12, 13, 14, 12, 14, 15 }, // Quad #3
       { 16, 17, 18, 16, 18, 19 }  // Big Quad
   };
   
#define NumTests  4
   GLfloat  colors[NumTests][4] = { 
       { 1.0f, 0.0f, 0.0f, 1.0f },
       { 0.0f, 1.0f, 0.0f, 1.0f },
       { 0.0f, 0.0f, 1.0f, 1.0f },
       { 1.0f, 1.0f, 0.0f, 0.0f }
   };

   GLint   numStencilBits;
   GLuint  stencilValues[NumTests] = { 
      0x7, // Result of test 0
      0x0, // Result of test 1
      0x2, // Result of test 2
      0xff // Result of test 3.  We need to fill this
           //  value in a run-time
   };


	display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
	if (display == EGL_NO_DISPLAY) {
		printf("Error: No display found!\n");
		return -1;
	}

	if (!eglInitialize(display, &egl_major, &egl_minor)) {
		printf("Error: eglInitialise failed!\n");
		return -1;
	}

	printf("Using display %p with EGL version %d.%d\n",
	       display, egl_major, egl_minor);

	printf("EGL Version \"%s\"\n", eglQueryString(display, EGL_VERSION));
	printf("EGL Vendor \"%s\"\n", eglQueryString(display, EGL_VENDOR));
	printf("EGL Extensions \"%s\"\n", eglQueryString(display, EGL_EXTENSIONS));

	/* get an appropriate EGL frame buffer configuration */
	eglChooseConfig(display, config_attribute_list, &config, 1, &num_config);

	/* create an EGL rendering context */
	context = eglCreateContext(display, config, EGL_NO_CONTEXT, context_attribute_list);
	if (context == EGL_NO_CONTEXT) {
		printf("Error: eglCreateContext failed: %d\n", eglGetError());
		return -1;
	}

	surface = eglCreatePbufferSurface(display, config, pbuffer_attribute_list);
	if (surface == EGL_NO_SURFACE) {
		printf("Error: eglCreatePbufferSurface failed: %d (%s)\n",
		       eglGetError(), eglStrError(eglGetError()));
		return -1;
	}

	if (!eglQuerySurface(display, surface, EGL_WIDTH, &width) ||
	    !eglQuerySurface(display, surface, EGL_HEIGHT, &height)) {
		printf("Error: eglQuerySurface failed: %d (%s)\n",
		       eglGetError(), eglStrError(eglGetError()));
		return -1;
	}
	printf("PBuffer: %dx%d\n", width, height);
        printf("GL Extensions \"%s\"\n", glGetString(GL_EXTENSIONS));

	/* connect the context to the surface */
	if (!eglMakeCurrent(display, surface, surface, context)) {
		printf("Error: eglMakeCurrent() failed: %d (%s)\n",
		       eglGetError(), eglStrError(eglGetError()));
		return -1;
	}

	vertex_shader = glCreateShader(GL_VERTEX_SHADER);
	if (!vertex_shader) {
		printf("Error: glCreateShader(GL_VERTEX_SHADER) failed: %d (%s)\n",
		       eglGetError(), eglStrError(eglGetError()));
		return -1;
	}

	glShaderSource(vertex_shader, 1, &vertex_shader_source, NULL);
	glCompileShader(vertex_shader);

	glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &ret);
	if (!ret) {
		char *log;

		printf("Error: vertex shader compilation failed!:\n");
		glGetShaderiv(vertex_shader, GL_INFO_LOG_LENGTH, &ret);

		if (ret > 1) {
			log = malloc(ret);
			glGetShaderInfoLog(vertex_shader, ret, NULL, log);
			printf("%s", log);
		}
		return -1;
	} else
		printf("Vertex shader compilation succeeded!\n");

	fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
	if (!fragment_shader) {
		printf("Error: glCreateShader(GL_FRAGMENT_SHADER) failed: %d (%s)\n",
		       eglGetError(), eglStrError(eglGetError()));
		return -1;
	}


	glShaderSource(fragment_shader, 1, &fragment_shader_source, NULL);
	glCompileShader(fragment_shader);

	glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &ret);
	if (!ret) {
		char *log;

		printf("Error: fragment shader compilation failed!:\n");
		glGetShaderiv(fragment_shader, GL_INFO_LOG_LENGTH, &ret);

		if (ret > 1) {
			log = malloc(ret);
			glGetShaderInfoLog(fragment_shader, ret, NULL, log);
			printf("%s", log);
		}
		return -1;
	} else
		printf("Fragment shader compilation succeeded!\n");

	program = glCreateProgram();
	if (!program) {
		printf("Error: failed to create program!\n");
		return -1;
	}

	glAttachShader(program, vertex_shader);
	glAttachShader(program, fragment_shader);

	glBindAttribLocation(program, 0, "in_position");

	glLinkProgram(program);

	glGetProgramiv(program, GL_LINK_STATUS, &ret);
	if (!ret) {
		char *log;

		printf("Error: program linking failed!:\n");
		glGetProgramiv(program, GL_INFO_LOG_LENGTH, &ret);

		if (ret > 1) {
			log = malloc(ret);
			glGetProgramInfoLog(program, ret, NULL, log);
			printf("%s", log);
		}
		return -1;
	} else
		printf("program linking succeeded!\n");

	GLint colorLoc = glGetUniformLocation(program, "u_color");
	glUseProgram(program);

	glViewport(0, 0, width, height);

       // Set the clear color
       glClearColor ( 0.0f, 0.0f, 0.0f, 0.0f );
       
       // Set the stencil clear value
       glClearStencil ( 0x1 );

       // Set the depth clear value
       glClearDepthf( 0.75f );

       // Enable the depth and stencil tests
       glEnable( GL_DEPTH_TEST );
       glEnable( GL_STENCIL_TEST );

	/* clear the color buffer */
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

        // Load the vertex position
        glVertexAttribPointer ( 0, 3, GL_FLOAT, 
                               GL_FALSE, 0, vVertices );
      
        glEnableVertexAttribArray ( 0 );
   
        // Test 0:
   //
   // Initialize upper-left region.  In this case, the
   //   stencil-buffer values will be replaced because the
   //   stencil test for the rendered pixels will fail the
   //   stencil test, which is
   //
   //        ref   mask   stencil  mask
   //      ( 0x7 & 0x3 ) < ( 0x1 & 0x3 )
   //
   //   The value in the stencil buffer for these pixels will
   //   be 0x7.
   //
   glStencilFunc( GL_LESS, 0x7, 0x3 );
   glStencilOp( GL_REPLACE, GL_DECR, GL_DECR );
   glDrawElements( GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, indices[0] );
 
   // Test 1:
   //
   // Initialize the upper-right region.  Here, we'll decrement
   //   the stencil-buffer values where the stencil test passes
   //   but the depth test fails.  The stencil test is
   //
   //        ref  mask    stencil  mask
   //      ( 0x3 & 0x3 ) > ( 0x1 & 0x3 )
   //
   //    but where the geometry fails the depth test.  The
   //    stencil values for these pixels will be 0x0.
   //
   glStencilFunc( GL_GREATER, 0x3, 0x3 );
   glStencilOp( GL_KEEP, GL_DECR, GL_KEEP );
   glDrawElements( GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, indices[1] );

   // Test 2:
   //
   // Initialize the lower-left region.  Here we'll increment 
   //   (with saturation) the stencil value where both the
   //   stencil and depth tests pass.  The stencil test for
   //   these pixels will be
   //
   //        ref  mask     stencil  mask
   //      ( 0x1 & 0x3 ) == ( 0x1 & 0x3 )
   //
   //   The stencil values for these pixels will be 0x2.
   //
   glStencilFunc( GL_EQUAL, 0x1, 0x3 );
   glStencilOp( GL_KEEP, GL_INCR, GL_INCR );
   glDrawElements( GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, indices[2] );

   // Test 3:
   //
   // Finally, initialize the lower-right region.  We'll invert
   //   the stencil value where the stencil tests fails.  The
   //   stencil test for these pixels will be
   //
   //        ref   mask    stencil  mask
   //      ( 0x2 & 0x1 ) == ( 0x1 & 0x1 )
   //
   //   The stencil value here will be set to ~((2^s-1) & 0x1),
   //   (with the 0x1 being from the stencil clear value),
   //   where 's' is the number of bits in the stencil buffer
   //
   glStencilFunc( GL_EQUAL, 0x2, 0x1 );
   glStencilOp( GL_INVERT, GL_KEEP, GL_KEEP );
   glDrawElements( GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, indices[3] );
   
   // Since we don't know at compile time how many stecil bits are present,
   //   we'll query, and update the value correct value in the
   //   stencilValues arrays for the fourth tests.  We'll use this value
   //   later in rendering.
   glGetIntegerv( GL_STENCIL_BITS, &numStencilBits );
   printf("num stencil bits: %i\n", numStencilBits);
   
   stencilValues[3] = ~(((1 << numStencilBits) - 1) & 0x1) & 0xff;

   // Use the stencil buffer for controlling where rendering will
   //   occur.  We diable writing to the stencil buffer so we
   //   can test against them without modifying the values we
   //   generated.
   glStencilMask( 0x0 );
   
   for ( int i = 0; i < NumTests; ++i )
   {
      glStencilFunc( GL_EQUAL, stencilValues[i], 0xff );
      glUniform4fv( colorLoc, 1, colors[i] );
      glDrawElements( GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, indices[4] );
   }

	glFlush();

	fflush(stdout);
        dump_gl_screen("/sdcard/egl2.bmp", width, height);

#ifdef HOOK
        close_hook();
#endif

	return 0;
}