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#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <sys/time.h>
#include <emscripten.h>
#include <emscripten/html5.h>
#include <GLES2/gl2.h>
#include <EGL/egl.h>
#include "mathlib.h"
#include "Shader.h"
// Shader code inlined
const char* orthographicVertex =
"attribute vec2 position; \n"
"attribute vec4 color; \n"
"uniform mat4 projection; \n"
"uniform mat4 model; \n"
"varying lowp vec4 VertexColor; \n"
"void main() { \n"
" vec4 fragmentPosition = projection * model * vec4(position, 1, 1); \n"
" gl_Position = fragmentPosition; \n"
" VertexColor = color; \n"
"}";
const char* orthographicFragment =
"varying lowp vec4 VertexColor; \n"
"void main() { \n"
" gl_FragColor = VertexColor; \n"
"}";
struct OrthographicProgramData {
GLuint shader;
struct {
int position;
int color;
} attributes;
struct {
int projection;
int model;
} uniformVariables;
};
struct OrthographicVertex {
Vector2 position;
Vector4 color;
};
// Create a triangle
struct TriangleObject {
OrthographicVertex vertices[3];
Vector2 velocity;
Vector2 position;
GLuint mVao;
GLuint mVbo;
Mat4x4 model;
void initialize(OrthographicProgramData* programData) {
useShader(programData->shader);
glGenVertexArrays(1, &mVao);
glBindVertexArray(mVao);
glGenBuffers(1, &mVbo);
glBindBuffer(GL_ARRAY_BUFFER, mVbo);
glBufferData(GL_ARRAY_BUFFER, 3 * sizeof(OrthographicVertex), &vertices[0], GL_STATIC_DRAW);
glEnableVertexAttribArray(programData->attributes.position);
glVertexAttribPointer(programData->attributes.position, 2, GL_FLOAT, GL_FALSE, sizeof(OrthographicVertex), (GLvoid *)0);
glEnableVertexAttribArray(programData->attributes.color);
glVertexAttribPointer(programData->attributes.color, 4, GL_FLOAT, GL_FALSE, sizeof(OrthographicVertex), (GLvoid *)offsetof(OrthographicVertex, color));
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
}
void render(OrthographicProgramData* programData) {
setShaderMat4(programData->uniformVariables.model, model);
glBindVertexArray(mVao);
glDrawArrays(GL_TRIANGLES, 0, 3);
glBindVertexArray(0);
}
};
struct Scene {
Mat4x4 projection;
TriangleObject triangleObject;
OrthographicProgramData programData;
bool isTerminated = false;
};
long long timeInMilliseconds(void) {
struct timeval tv;
gettimeofday(&tv,NULL);
return (((long long)tv.tv_sec)*1000)+(tv.tv_usec/1000);
}
long elapsedTime = 0;
long lastTime = 0;
int numFrames = 0;
EM_BOOL update(double time, void* userData);
EM_BOOL runScene(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData);
EM_BOOL terminateScene(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData);
int main() {
printf("Initializing the canvas...\n");
emscripten_set_canvas_element_size( "#wasm_canvas", 800, 600 );
EmscriptenWebGLContextAttributes attrs;
emscripten_webgl_init_context_attributes(&attrs);
attrs.enableExtensionsByDefault = 1;
attrs.majorVersion = 3;
attrs.minorVersion = 0;
EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context = emscripten_webgl_create_context( "#wasm_canvas", &attrs );
if (!context)
{
attrs.majorVersion = 1;
context = emscripten_webgl_create_context( "#wasm_canvas", &attrs );
if (context) printf("Skipping test: WebGL 3.0 is not available.\n");
else printf("Test failed: WebGL is not available!\n");
return 0;
}
emscripten_webgl_make_context_current(context);
printf("Canvas ready.\n");
emscripten_set_click_callback("#wasm_canvas_play_button", NULL, false, runScene);
emscripten_set_click_callback("#wasm_canvas_stop_button", NULL, false, terminateScene);
return EXIT_SUCCESS;
}
Scene scene;
EM_BOOL runScene(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData) {
scene.programData = OrthographicProgramData();
printf("Compiling shaders...\n");
scene.programData.shader = loadShader(orthographicVertex, orthographicFragment);
printf("Shaders compiled.\n");
printf("Initializing scene...\n");
useShader(scene.programData.shader);
scene.programData.attributes.position = getShaderAttribute(scene.programData.shader, "position");
scene.programData.attributes.color = getShaderAttribute(scene.programData.shader, "color");
scene.programData.uniformVariables.projection = getShaderUniform(scene.programData.shader, "projection");
scene.programData.uniformVariables.model = getShaderUniform(scene.programData.shader, "model");
scene.triangleObject = TriangleObject();
scene.triangleObject.vertices[0] = { Vector2 { -100, -50 }, Vector4 { 1.f, 0.f, 0.f, 1.f }};
scene.triangleObject.vertices[1] = { Vector2 { 0, 50 }, Vector4 { 0.f, 1.f, 0.f, 1.f }};
scene.triangleObject.vertices[2] = { Vector2 { 100, -50 }, Vector4 { 0.f, 0.f, 1.f, 1.f }};
scene.triangleObject.position = { 320.f, 600.f - 100.f };
scene.triangleObject.initialize(&scene.programData);
scene.projection = Mat4x4().getOrthographicMatrix(0, 800, 0, 600);
scene.isTerminated = false;
printf("Scene initialized.\n");
emscripten_request_animation_frame_loop(update, &scene);
return true;
}
EM_BOOL update(double time, void* userData) {
Scene* scene = (Scene*)userData;
if (scene->isTerminated) {
return false;
}
if (lastTime == 0) {
lastTime = time;
return true;
}
long deltaTime = time - lastTime;
lastTime = time;
elapsedTime += deltaTime;
numFrames++;
if (elapsedTime >= 1000.0) {
printf("Frames Per Second: %d\n", numFrames);
numFrames = 0;
elapsedTime = 0.0;
}
float deltaTimeSeconds = static_cast<float>(deltaTime) / 1000.f;
// Update
scene->triangleObject.velocity = scene->triangleObject.velocity + Vector2 { 0, static_cast<float>(-9.8 * deltaTimeSeconds) };
scene->triangleObject.position = scene->triangleObject.position + scene->triangleObject.velocity * deltaTimeSeconds;
scene->triangleObject.model = Mat4x4().translateByVec2(scene->triangleObject.position);
// Render
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glDepthMask(GL_TRUE);
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClearDepth(1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
useShader(scene->programData.shader);
setShaderMat4(scene->programData.uniformVariables.projection, scene->projection);
scene->triangleObject.render(&scene->programData);
return true;
}
EM_BOOL terminateScene(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData) {
scene.isTerminated = true;
glDeleteVertexArrays(1, &scene.triangleObject.mVao);
glDeleteBuffers(1, &scene.triangleObject.mVbo);
glDeleteProgram(scene.programData.shader);
return true;
}
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