add instanced draw with uniform buffer

1 files changed, 27 insertions, 4 deletions

diff --git a/main.c b/main.c
index b26de0d..e6aded0 100644
--- a/main.c
+++ b/main.c
@@ -42,16 +42,29 @@ static const char
 vs_src[] =
   "#version 320 es\n"
   "\n"
+  "layout (std140, binding = 0) uniform particles {\n"
+  "  mediump vec4 positions[1000];\n"
+  "  mediump vec4 velocities[1000];\n"
+  "  mediump vec4 colors[1000];\n"
+  "};\n"
+  "\n"
   "layout (location = 0) in mediump vec3 pos;\n"
   "\n"
   "void main() {\n"
-  "  gl_Position = vec4(pos.x, pos.y, pos.z, 1);\n"
+  "  mediump float ofs = 0.002 * float(gl_InstanceID - 500);\n"
+  "  gl_Position = vec4(pos.x - ofs, pos.y, pos.z, 1);\n"
   "}\n";
 
 static const char
 fs_src[] =
   "#version 320 es\n"
   "\n"
+  "layout (std140, binding = 0) uniform particles {\n"
+  "  mediump vec4 positions[1000];\n"
+  "  mediump vec4 velocities[1000];\n"
+  "  mediump vec4 colors[1000];\n"
+  "};\n"
+  "\n"
   "out mediump vec4 color;\n"
   "\n"
   "uniform mediump float time;\n"
@@ -222,7 +235,7 @@ ctx_init(context_t * const ctx) {
   }
 
   // init times ring buffer
-  memset(ctx->times, 0, MAX_TIMES * sizeof(uint32_t) * 2);
+  // memset(ctx->times, 0, sizeof(ctx->times));
   ctx->times_ofs = 0;
 
   // init flags
@@ -288,7 +301,7 @@ handle_events(
       if (ev.user.code == EVENT_CODE_TIMER) {
         uint32_t sum = 0;
 
-        #pragma omp parallel for reduction(+:sum)
+        // #pragma omp parallel for reduction(+:sum)
         for (int i = 0; i < MAX_TIMES; i++) {
           sum += ctx->times[i].draw_end - ctx->times[i].draw_start;
         }
@@ -339,6 +352,16 @@ int main(int argc, char *argv[]) {
   glGenVertexArrays(1, &vao);
   glBindVertexArray(vao);
 
+  // generate uniform buffer
+  GLuint ubo;
+  glGenBuffers(1, &ubo);
+  glBindBuffer(GL_UNIFORM_BUFFER, ubo);
+  glBufferData(GL_UNIFORM_BUFFER, 1000 * 3 * 4 * sizeof(GLfloat), NULL, GL_STATIC_DRAW);
+  glBindBuffer(GL_UNIFORM_BUFFER, 0);
+
+  // bind uniform buffer to slot 0
+  glBindBufferBase(GL_UNIFORM_BUFFER, 2, ubo);
+
   // generate vertex buffer
   GLuint vbo;
   glGenBuffers(1, &vbo);
@@ -373,7 +396,7 @@ int main(int argc, char *argv[]) {
 
     // draw
     glBindVertexArray(vao);
-    glDrawArrays(GL_TRIANGLES, 0, 3);
+    glDrawArraysInstanced(GL_TRIANGLES, 0, 3, 1000);
     glBindVertexArray(0);
 
     // swap buffer