Added grid debug rendering primitive.

src/srender.c

@@ -25,8 +25,8 @@ typedef struct srview {
 } srview;
 
 typedef struct srcmdbuf {
+  int nbufsize;
   int ncmds;
-  int idx;
   srcmd* cmds;
 } srcmdbuf;
 
@@ -48,6 +48,13 @@ typedef union srvrtxdata {
   };
 } srvrtxdata;
 
+//
+// Vertex Buffer Object for all debug objects (coord frame, grid, cube, ...)
+//
+const GLint DEBUG_VBO_SIZE = 1024;
+GLuint gDebugShapesVBOId = 0;
+GLuint gDebugShapesVAId = 0;
+
 //
 // Simple Mesh Data
 //
@@ -58,9 +65,13 @@ typedef struct srmeshdata {
   GLuint vao_id;
   GLuint vb_id;
   GLuint idb_id;
+
+  GLuint count;
+  GLenum mode;
 } srmeshdata;
 
 static srmeshdata gCoordFrameMesh = {0};
+static srmeshdata gGridMesh = {0};
 
 typedef struct srshader {
   const char* vert_fname;
@@ -211,11 +222,14 @@ void init_shaders() {
 void init_debug_meshes() {
   assert(gCoordFrameMesh.nvertices == 0);
 
-  glGenVertexArrays(1, &gCoordFrameMesh.vao_id);
+  glGenVertexArrays(1, &gDebugShapesVAId);
-  glBindVertexArray(gCoordFrameMesh.vao_id);
+  glBindVertexArray(gDebugShapesVAId);
 
-  glGenBuffers(1, &gCoordFrameMesh.vb_id);
+  glGenBuffers(1, &gDebugShapesVBOId);
-  glBindBuffer(GL_ARRAY_BUFFER, gCoordFrameMesh.vb_id);
+  glBindBuffer(GL_ARRAY_BUFFER, gDebugShapesVBOId);
+  glBufferData(GL_ARRAY_BUFFER, sizeof(union srvrtxdata) * DEBUG_VBO_SIZE, NULL, GL_STATIC_DRAW);
+
+  GLintptr dbg_vbuf_offset = 0;
 
   glEnableVertexAttribArray(0);
   glVertexAttribPointer(
@@ -254,6 +268,11 @@ void init_debug_meshes() {
       (sizeof(srvrtxdata)),
       (void*)(sizeof(float) * 9));
 
+  //
+  // Coordinate Frame
+  //
+  gCoordFrameMesh.vao_id = gDebugShapesVAId;
+  gCoordFrameMesh.vb_id = gDebugShapesVBOId;
   gCoordFrameMesh.nvertices = 6;
 
   srvrtxdata coord_frame_vertices[] = {
@@ -267,12 +286,12 @@ void init_debug_meshes() {
       {0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0, 0, 255, 255}};
   GLuint coord_frame_indices[] = {0, 1, 2, 3, 4, 5};
 
-  glBufferData(
+  glBufferSubData(
       GL_ARRAY_BUFFER,
+      dbg_vbuf_offset,
       sizeof(coord_frame_vertices),
-      coord_frame_vertices,
+      coord_frame_vertices);
-      GL_STATIC_DRAW);
+  dbg_vbuf_offset = sizeof (coord_frame_vertices);
-  glBindBuffer(GL_ARRAY_BUFFER, 0);
 
   glGenBuffers(1, &gCoordFrameMesh.idb_id);
   glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gCoordFrameMesh.idb_id);
@@ -281,7 +300,69 @@ void init_debug_meshes() {
       sizeof(coord_frame_indices),
       coord_frame_indices,
       GL_STATIC_DRAW);
-  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+
+  gCoordFrameMesh.mode = GL_LINES;
+  gCoordFrameMesh.count = 6;
+
+  //
+  // Coordinate Frame
+  //
+  gGridMesh.vao_id = gDebugShapesVAId;
+  gGridMesh.vb_id = gDebugShapesVBOId;
+  gGridMesh.nvertices = 44;
+
+  srvrtxdata* grid_vertices = calloc(44, sizeof(srvrtxdata));
+  srvrtxdata grid_def_vertex = {
+      0.f, 0.f, 0.f, 1.f,
+      0.f, 1.f, 0.f,
+      0.f, 0.f,
+      255, 255, 255, 255
+  };
+  // lines along parallel to x axis
+  for (int i = 0; i <= 10; i++) {
+    memcpy (&grid_vertices[2*i], &grid_def_vertex, sizeof(srvrtxdata));
+    memcpy (&grid_vertices[2*i + 1], &grid_def_vertex, sizeof(srvrtxdata));
+    grid_vertices[2 * i].pos[0] = -5.0f + i * 1.0f;
+    grid_vertices[2 * i].pos[2] = 5.0f;
+    grid_vertices[2 * i + 1].pos[0] = -5.0f + i * 1.0f;
+    grid_vertices[2 * i + 1].pos[2] = -5.0f;
+  }
+  // lines parallel to z axis
+  for (int i = 11; i <= 21; i++) {
+    memcpy (&grid_vertices[2*i], &grid_def_vertex, sizeof(srvrtxdata));
+    memcpy (&grid_vertices[2*i + 1], &grid_def_vertex, sizeof(srvrtxdata));
+    grid_vertices[2 * i].pos[0] = -5.0f;
+    grid_vertices[2 * i].pos[2] = -5.0f + (i - 11) * 1.0f;
+    grid_vertices[2 * i + 1].pos[0] = 5.0f;
+    grid_vertices[2 * i + 1].pos[2] = -5.0f + (i - 11) * 1.0f;
+  }
+
+  glBindBuffer(GL_ARRAY_BUFFER, gDebugShapesVBOId);
+  glBufferSubData(
+      GL_ARRAY_BUFFER,
+      dbg_vbuf_offset,
+      sizeof(srvrtxdata) * 44,
+      grid_vertices);
+  dbg_vbuf_offset += sizeof (srvrtxdata) * 44;
+
+  free(grid_vertices);
+
+  GLuint grid_indices[44];
+  for (int i = 0; i < 22; i++) {
+    grid_indices[2 * i] = 2*i + 6;
+    grid_indices[2 * i + 1] = (2*i+1) + 6;
+  }
+
+  glGenBuffers(1, &gGridMesh.idb_id);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gGridMesh.idb_id);
+  glBufferData(
+      GL_ELEMENT_ARRAY_BUFFER,
+      sizeof(grid_indices),
+      grid_indices,
+      GL_STATIC_DRAW);
+
+  gGridMesh.mode = GL_LINES;
+  gGridMesh.count = 44;
 
   glBindVertexArray(0);
 };
@@ -419,7 +500,17 @@ void srndr_run_frame_command(const srcmd* cmd) {
   glBindVertexArray(gCoordFrameMesh.vao_id);
 
   glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gCoordFrameMesh.idb_id);
-  glDrawElements(GL_LINES, 6, GL_UNSIGNED_INT, (void*)0);
+  glDrawElements(gCoordFrameMesh.mode, gCoordFrameMesh.count, GL_UNSIGNED_INT, (void*)0);
+
+  glBindBuffer(GL_ARRAY_BUFFER, 0);
+  glBindVertexArray(0);
+}
+
+void srndr_run_grid_command(const srcmd* cmd) {
+  glBindVertexArray(gGridMesh.vao_id);
+
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gGridMesh.idb_id);
+  glDrawElements(gGridMesh.mode, gGridMesh.count, GL_UNSIGNED_INT, (void*)0);
 
   glBindBuffer(GL_ARRAY_BUFFER, 0);
   glBindVertexArray(0);
@@ -455,6 +546,9 @@ void srndr_render(srndr* srndr, srview* sview, srcmdbuf* scmdbuf) {
       case SRndrCmdTypeFrame:
         srndr_run_frame_command(cmd);
         break;
+      case SRndrCmdTypeGrid:
+        srndr_run_grid_command(cmd);
+        break;
       default:
         gLog("Invalid command type %d at index %d", cmd->type, i);
         break;
@@ -469,19 +563,19 @@ void srndr_render(srndr* srndr, srview* sview, srcmdbuf* scmdbuf) {
 //
 srcmdbuf* srcmdbuf_create(unsigned int size_max) {
   srcmdbuf* result = malloc(sizeof(srcmdbuf));
-  result->ncmds = size_max;
+  result->nbufsize = size_max;
-  result->idx = 0;
+  result->ncmds = 0;
   result->cmds = calloc(sizeof(srcmd), size_max);
 
   return result;
 }
 
-void srcmdbuf_clear(srcmdbuf* cmdbuf) { cmdbuf->idx = 0; }
+void srcmdbuf_clear(srcmdbuf* cmdbuf) { cmdbuf->ncmds = 0; }
 
 srcmd* srcmd_create(srcmdbuf* cmdbuf) {
-  if (cmdbuf->idx == cmdbuf->ncmds) {
+  if (cmdbuf->ncmds == cmdbuf->nbufsize) {
     gLog("Warning: number of render commands maxed out!");
     return NULL;
   }
-  return &(cmdbuf->cmds[cmdbuf->idx++]);
+  return &(cmdbuf->cmds[cmdbuf->ncmds++]);
 }

src/srender.h

@@ -20,8 +20,8 @@ typedef enum {
 } SRndrCmdType;
 
 typedef struct srcmd {
-	simd4x4f mat;
+  simd4x4f mat;
-	simd4f color;
+  simd4f color;
   SRndrCmdType type;
 } srcmd;
 
@@ -46,7 +46,7 @@ void srview_get_output_texture(srview* sv, GLuint* texture);
 // Command Buffer and Commands
 //
 srcmdbuf* srcmdbuf_create(unsigned int size_max);
-void srcmdbuf_clear (srcmdbuf* cmdbuf);
+void srcmdbuf_clear(srcmdbuf* cmdbuf);
 srcmd* srcmd_create(srcmdbuf* cmdbuf);
 
 void srndr_render(srndr* srndr, srview* sview, srcmdbuf* scmdbuf);

src/vissim.cc

@@ -170,7 +170,18 @@ void DoRender() {
       simd4f_create(1.f, 1.f, 1.f, 1.f),
       simd4f_create(0.f, 0.f, 0.f, 1.f),
       simd4f_create(0.f, 1.f, 0.f, 1.f));
-  simd4x4f_ortho(&proj, -5.0f, 5.0f, -5.0f, 5.0f, -5.0f, 5.0f);
+
+  float view_width = content_avail.x / 50.f;
+  float view_height = content_avail.y / 50.f;
+
+  simd4x4f_ortho(
+      &proj,
+      -0.5f * view_width,
+      0.5f * view_width,
+      -0.5f * view_height,
+      0.5f * view_height,
+      -50.0f,
+      50.0f);
   srview_set_view(gView, view);
   srview_set_proj(gView, proj);
 
@@ -181,6 +192,11 @@ void DoRender() {
   simd4x4f_identity(&cmd->mat);
   cmd->color = simd4f_create(1.f, 1.f, 1.f, 1.f);
 
+  cmd = srcmd_create(gRndrCmds);
+  cmd->type = SRndrCmdTypeGrid;
+  simd4x4f_identity(&cmd->mat);
+  cmd->color = simd4f_create(1.f, 1.f, 1.f, 1.f);
+
   // Perform the actual render
   srndr_render(gRndr, gView, gRndrCmds);
   GLuint view_texture;