blob: ee2b34e26809eb03db5510275e918d0f5be7aef5 [file] [log] [blame]
/*
* Copyright 2013 The Emscripten Authors. All rights reserved.
* Emscripten is available under two separate licenses, the MIT license and the
* University of Illinois/NCSA Open Source License. Both these licenses can be
* found in the LICENSE file.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <emscripten.h>
#define BUFFER_OFFSET(i) ((char *)NULL + (i))
static const int WINDOWS_SIZE = 500;
static GLfloat vertices[] = { 0.0f, 250.f, 0.0f,
-250.f, -250.f, 0.0f,
250.f, -250.f, 0.0f };
static GLfloat vertices2[] = { 0.0f, 250.f, -1.0f,
-250.f, -250.f, -1.0f,
250.f, -250.f, -1.0f };
static GLuint shaderProgram = 0;
static GLuint verticesVBO = 0;
static GLuint verticesVBO2 = 0;
static unsigned char backgroundColor[4] = {255, 255, 255, 255};
static unsigned char triangleColor[4] = {255, 0, 0, 255};
static unsigned char triangleColor2[4] = {0, 255, 0, 255};
static char vertexShaderSrc[] =
"precision highp float;"
"precision highp int;"
"uniform mat4 u_mvpMatrix;"
"uniform vec4 u_color;"
"attribute vec3 a_position;"
"varying vec4 v_color;"
"void main() {"
" gl_Position = u_mvpMatrix * vec4(a_position, 1.0);"
" v_color = u_color;"
"}"
;
static char fragmentShaderSrc[] =
"precision highp float;"
"precision highp int;"
"varying vec4 v_color;"
"void main() {"
" gl_FragColor = v_color;"
"}"
;
static GLuint createShader(const char *source, int type) {
GLuint shader = glCreateShader(type);
glShaderSource(shader, 1, (const GLchar**)(&source), NULL);
glCompileShader(shader);
return shader;
}
static GLuint createShaderProgram(const char *vertexShaderSrc, const char *fragmentShaderSrc) {
GLuint program = glCreateProgram();
glAttachShader(program, createShader(vertexShaderSrc, GL_VERTEX_SHADER));
glAttachShader(program, createShader(fragmentShaderSrc, GL_FRAGMENT_SHADER));
glLinkProgram(program);
return program;
}
void ortho(float left, float right, float bottom, float top, float nearVal, float farVal, GLfloat *projMatrix) {
float tx = -(right+left)/(right-left);
float ty = -(top+bottom)/(top-bottom);
float tz = -(farVal+nearVal)/(farVal-nearVal);
memset(projMatrix, 0, 16 * sizeof(GLfloat));
projMatrix[0] = 2.0f / (right-left);
projMatrix[3] = tx;
projMatrix[1*4+1] = 2.0f / (top-bottom);
projMatrix[1*4+3] = ty;
projMatrix[2*4+2] = -2.0f / (farVal-nearVal);
projMatrix[2*4+3] = tz;
projMatrix[3*4+3] = 1.0f;
}
static void initGlObjects() {
glGenBuffers(1, &verticesVBO);
glBindBuffer(GL_ARRAY_BUFFER, verticesVBO);
glBufferData(GL_ARRAY_BUFFER, 9*sizeof(float), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glGenBuffers(1, &verticesVBO2);
glBindBuffer(GL_ARRAY_BUFFER, verticesVBO2);
glBufferData(GL_ARRAY_BUFFER, 9*sizeof(float), vertices2, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
shaderProgram = createShaderProgram(vertexShaderSrc, fragmentShaderSrc);
}
static void drawTriangle(GLuint verticesVBO, unsigned char r, unsigned char g, unsigned char b, unsigned char a) {
glUseProgram(shaderProgram);
GLuint posLoc = glGetAttribLocation(shaderProgram, "a_position");
GLuint mvpLoc = glGetUniformLocation(shaderProgram, "u_mvpMatrix");
GLuint colorLoc = glGetUniformLocation(shaderProgram, "u_color");
GLfloat mvpMat[16];
ortho(-WINDOWS_SIZE/2, WINDOWS_SIZE/2, -WINDOWS_SIZE/2, WINDOWS_SIZE/2, -100, 100, mvpMat);
glUniformMatrix4fv(mvpLoc, 1, GL_FALSE, mvpMat);
glUniform4f(colorLoc, r/255.f, g/255.f, b/255.f, a/255.f);
glBindBuffer(GL_ARRAY_BUFFER, verticesVBO);
glEnableVertexAttribArray(posLoc);
glVertexAttribPointer(posLoc, 3, GL_FLOAT, GL_FALSE, 3*sizeof(float), BUFFER_OFFSET(0));
glDrawArrays(GL_TRIANGLES, 0, 3);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glUseProgram(0);
}
// Draw a red triangle on a white background. If antialiasing is disabled, resulting pixels
// will only have white and red colors. If antialiasing is enabled, there will be pixels
// whose color is different from red and white.
static int testAntiAliasing(bool activated) {
glViewport(0, 0, WINDOWS_SIZE, WINDOWS_SIZE);
glClearColor(backgroundColor[0]/255.f, backgroundColor[1]/255.f, backgroundColor[2]/255.f, backgroundColor[3]/255.f);
glClear(GL_COLOR_BUFFER_BIT);
drawTriangle(verticesVBO, triangleColor[0], triangleColor[1], triangleColor[2], triangleColor[3]);
bool antialiased = false;
unsigned char buffer[(WINDOWS_SIZE*WINDOWS_SIZE)*4];
glReadPixels(0, 0, WINDOWS_SIZE, WINDOWS_SIZE, GL_RGBA, GL_UNSIGNED_BYTE, &buffer[0]);
glFinish();
for (unsigned int i = 0 ; i < WINDOWS_SIZE ; ++i) {
for (unsigned int j = 0 ; j < WINDOWS_SIZE ; ++j) {
unsigned char r = buffer[4*(i*WINDOWS_SIZE+j)];
unsigned char g = buffer[4*(i*WINDOWS_SIZE+j)+1];
unsigned char b = buffer[4*(i*WINDOWS_SIZE+j)+2];
unsigned char a = buffer[4*(i*WINDOWS_SIZE+j)+3];
if ((r == backgroundColor[0] && g == backgroundColor[1] && b == backgroundColor[2] && a == backgroundColor[3]) ||
(r == triangleColor[0] && g == triangleColor[1] && b == triangleColor[2] && a == triangleColor[3])) {
continue;
} else {
antialiased = true;
break;
}
}
}
return (activated && antialiased) || (!activated && !antialiased);
}
// Draw a red triangle with depth equals to 0 then a green triangle whose depth equals -1.
// If there is an attached depth buffer, the resulting image will be a red triangle. If not,
// the resulting image will be a green triangle.
static int testDepth(bool activated) {
glViewport(0, 0, WINDOWS_SIZE, WINDOWS_SIZE);
glClearColor(backgroundColor[0]/255.f, backgroundColor[1]/255.f, backgroundColor[2]/255.f, backgroundColor[3]/255.f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
drawTriangle(verticesVBO, triangleColor[0], triangleColor[1], triangleColor[2], triangleColor[3]);
drawTriangle(verticesVBO2, triangleColor2[0], triangleColor2[1], triangleColor2[2], triangleColor2[3]);
glDisable(GL_DEPTH_TEST);
// read the pixel at the center of the resulting image.
unsigned char buffer[4];
glReadPixels(WINDOWS_SIZE/2, WINDOWS_SIZE/2, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &buffer[0]);
bool frontTriangleColor = (buffer[0] == triangleColor[0] && buffer[1] == triangleColor[1] &&
buffer[2] == triangleColor[2] && buffer[3] == triangleColor[3]);
bool backTriangleColor = (buffer[0] == triangleColor2[0] && buffer[1] == triangleColor2[1] &&
buffer[2] == triangleColor2[2] && buffer[3] == triangleColor2[3]);
return (activated && frontTriangleColor) || (!activated && backTriangleColor);
}
// The stencil function is set to GL_LEQUAL so fragments will be written to the
// back buffer only if the ref value is less or equal than the one in the stencil buffer.
// The content of the stencil buffer is initialized to 0xFF.
// First draw a red triangle whose stencil ref value is 0x1.
// Then draw a green triangle whose stencil ref value is 0xFF.
// If there is an attached stencil buffer, the resulting image will be a red triangle. If not,
// the resulting image will be a green triangle.
static int testStencil(bool activated) {
glViewport(0, 0, WINDOWS_SIZE, WINDOWS_SIZE);
glClearColor(backgroundColor[0]/255.f, backgroundColor[1]/255.f, backgroundColor[2]/255.f, backgroundColor[3]/255.f);
glClearStencil(0xFF);
glStencilOp(GL_KEEP,GL_KEEP,GL_REPLACE);
glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
glEnable(GL_STENCIL_TEST);
glStencilFunc(GL_LEQUAL, 0x1, 0xFF);
drawTriangle(verticesVBO, triangleColor[0], triangleColor[1], triangleColor[2], triangleColor[3]);
glStencilFunc(GL_LEQUAL, 0xFF, 0xFF);
drawTriangle(verticesVBO, triangleColor2[0], triangleColor2[1], triangleColor2[2], triangleColor2[3]);
glDisable(GL_STENCIL_TEST);
unsigned char buffer[4];
glReadPixels(WINDOWS_SIZE/2, WINDOWS_SIZE/2, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &buffer[0]);
bool firstTriangleColor = (buffer[0] == triangleColor[0] && buffer[1] == triangleColor[1] &&
buffer[2] == triangleColor[2] && buffer[3] == triangleColor[3]);
bool secondTriangleColor = (buffer[0] == triangleColor2[0] && buffer[1] == triangleColor2[1] &&
buffer[2] == triangleColor2[2] && buffer[3] == triangleColor2[3]);
return (activated && firstTriangleColor) || (!activated && secondTriangleColor);
}
// Clear to a color with alpha = 0. If alpha is enabled then all pixels will have alpha = 0.
// If alpha is disabled then pixels will have alpha of 255
static int testAlpha(bool activated) {
glViewport(0, 0, WINDOWS_SIZE, WINDOWS_SIZE);
glClearColor(backgroundColor[0]/255.f, backgroundColor[1]/255.f, backgroundColor[2]/255.f, 0.0);
glClear(GL_COLOR_BUFFER_BIT);
bool hasAlpha = true;
unsigned char buffer[(WINDOWS_SIZE*WINDOWS_SIZE)*4];
glReadPixels(0, 0, WINDOWS_SIZE, WINDOWS_SIZE, GL_RGBA, GL_UNSIGNED_BYTE, &buffer[0]);
glFinish();
for (unsigned int i = 0 ; i < WINDOWS_SIZE ; ++i) {
for (unsigned int j = 0 ; j < WINDOWS_SIZE ; ++j) {
unsigned char r = buffer[4*(i*WINDOWS_SIZE+j)];
unsigned char g = buffer[4*(i*WINDOWS_SIZE+j)+1];
unsigned char b = buffer[4*(i*WINDOWS_SIZE+j)+2];
unsigned char a = buffer[4*(i*WINDOWS_SIZE+j)+3];
if (r == backgroundColor[0] && g == backgroundColor[1] && b == backgroundColor[2] && a == 0) {
continue;
} else {
hasAlpha = false;
break;
}
}
}
return (activated && hasAlpha) || (!activated && !hasAlpha);
}
static bool antiAliasingActivated = false;
static bool depthActivated = false;
static bool stencilActivated = false;
static bool alphaActivated = false;
static int result = 0;
static int resultAA = 0;
static int resultDepth = 0;
static int resultStencil = 0;
static int resultAlpha = 0;
static void draw() {
if (!resultAA) resultAA = testAntiAliasing(antiAliasingActivated);
if (!resultDepth) resultDepth = testDepth(depthActivated);
if (!resultStencil) resultStencil = testStencil(stencilActivated);
if (!resultAlpha) resultAlpha = testAlpha(alphaActivated);
result = resultAA && resultDepth && resultStencil && resultAlpha;
}
extern int webglAntialiasSupported(void);
extern int webglDepthSupported(void);
extern int webglStencilSupported(void);
extern int webglAlphaSupported(void);
// Check attributes support in the WebGL implementation (see test_webgl_context_attributes function in test_browser.py)
// Tests will succeed if they are not.
static void checkContextAttributesSupport() {
if (!webglAntialiasSupported()) {
resultAA = 1;
EM_ASM(out('warning: no antialiasing\n'));
}
if (!webglDepthSupported()) {
resultDepth = 1;
EM_ASM(out('warning: no depth\n'));
}
if (!webglStencilSupported()) {
resultStencil = 1;
EM_ASM(out('warning: no stencil\n'));
}
if (!webglAlphaSupported()) {
resultAlpha = 1;
EM_ASM(out('warning: no alpha\n'));
}
}