diff options
Diffstat (limited to 'main.c')
| -rw-r--r-- | main.c | 85 |
1 files changed, 64 insertions, 21 deletions
@@ -1,6 +1,7 @@ #include <stdbool.h> #include <stdlib.h> +#include <openssl/rand.h> #include <GL/glew.h> #include <SDL2/SDL.h> @@ -37,36 +38,35 @@ typedef struct { static const float verts[] = { - -0.5, 0.5, 0, - 0.5, 0.5, 0, - 0.0, -0.5, 0, + -1, 1, 0, + 1, 1, 0, + 0.0, -1, 0, }; static const char vs_src[] = "#version 320 es\n" "\n" - "layout (std140, binding = 0) buffer particles {\n" - " mediump vec4 positions[" S(NUM_PARTICLES) "];\n" - " mediump vec4 velocities[" S(NUM_PARTICLES) "];\n" - " mediump vec4 colors[" S(NUM_PARTICLES) "];\n" + "layout (std430, binding = 1) buffer particles {\n" + " highp vec4 positions[" S(NUM_PARTICLES) "];\n" + " highp vec4 velocities[" S(NUM_PARTICLES) "];\n" + " highp vec4 colors[" S(NUM_PARTICLES) "];\n" "};\n" "\n" "layout (location = 0) in mediump vec3 pos;\n" "\n" "void main() {\n" - " mediump float ofs = 0.002 * float(gl_InstanceID - 500);\n" - " gl_Position = vec4(pos.x - ofs, pos.y, pos.z, 1);\n" + " gl_Position = positions[gl_InstanceID] + 0.025 * vec4(pos, 1);\n" "}\n"; static const char fs_src[] = "#version 320 es\n" "\n" - "layout (std140, binding = 0) buffer particles {\n" - " mediump vec4 positions[" S(NUM_PARTICLES) "];\n" - " mediump vec4 velocities[" S(NUM_PARTICLES) "];\n" - " mediump vec4 colors[" S(NUM_PARTICLES) "];\n" + "layout (std430, binding = 1) buffer particles {\n" + " highp vec4 positions[" S(NUM_PARTICLES) "];\n" + " highp vec4 velocities[" S(NUM_PARTICLES) "];\n" + " highp vec4 colors[" S(NUM_PARTICLES) "];\n" "};\n" "\n" "out mediump vec4 color;\n" @@ -340,6 +340,56 @@ static Uint32 timer_cb( return interval; } +static GLuint +init_particles(void) { + // create shader storage buffer + GLuint ssbo; + glGenBuffers(1, &ssbo); + + // generate seed data + uint8_t seeds[4 * NUM_PARTICLES]; + if (!RAND_bytes(seeds, 4 * NUM_PARTICLES)) { + SDL_Log("RAND_bytes() failed"); + exit(EXIT_FAILURE); + } + + // populate data + float data[3 * 4 * NUM_PARTICLES]; + #pragma omp parallel for + for (int i = 0; i < NUM_PARTICLES; i++) { + float x = 2.0 * seeds[4 * i + 0] / 0xFF - 1.0, + y = 2.0 * seeds[4 * i + 1] / 0xFF - 1.0; + + // SDL_Log("%f,%f", x, y); + + // populate position + data[4 * i + 0] = x; + data[4 * i + 1] = y; + data[4 * i + 2] = 0.0; + data[4 * i + 3] = 1.0; + + // populate random velocity + data[4 * (NUM_PARTICLES + i) + 0] = 2.0 * seeds[4 * i + 2] / 0xFF - 1.0; + data[4 * (NUM_PARTICLES + i) + 1] = 2.0 * seeds[4 * i + 3] / 0xFF - 1.0; + + // populate colors + data[4 * (2 * NUM_PARTICLES + i) + 0] = ((i % 3) == 0) ? 1.0 : 0.0; + data[4 * (2 * NUM_PARTICLES + i) + 1] = ((i % 3) == 1) ? 1.0 : 0.0; + data[4 * (2 * NUM_PARTICLES + i) + 2] = ((i % 3) == 2) ? 1.0 : 0.0; + data[4 * (2 * NUM_PARTICLES + i) + 3] = 1.0; + } + + // populate buffer + glBindBuffer(GL_SHADER_STORAGE_BUFFER, ssbo); + glBufferData(GL_SHADER_STORAGE_BUFFER, sizeof(data), data, GL_STATIC_DRAW); + glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0); + + glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, ssbo); + + // return buffer + return ssbo; +} + int main(int argc, char *argv[]) { UNUSED(argc); UNUSED(argv); @@ -357,14 +407,7 @@ int main(int argc, char *argv[]) { glBindVertexArray(vao); // generate shader storage buffer - GLuint ssbo; - glGenBuffers(1, &ssbo); - glBindBuffer(GL_SHADER_STORAGE_BUFFER, ssbo); - glBufferData(GL_SHADER_STORAGE_BUFFER, NUM_PARTICLES * 3 * 4 * sizeof(GLfloat), NULL, GL_STATIC_DRAW); - glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0); - - // bind uniform buffer to slot 0 - // glBindBufferBase(GL_UNIFORM_BUFFER, 2, ubo); + GLuint ssbo = init_particles(); // generate vertex buffer GLuint vbo; |