archivemuh

archive/dusksdl2/display/mesh/mesh.c

@@ -0,0 +1,82 @@
+/**
+ * Copyright (c) 2025 Dominic Masters
+ * 
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "mesh.h"
+#include "util/memory.h"
+#include "assert/assert.h"
+
+#include "console/console.h"
+
+void meshInit(
+  mesh_t *mesh,
+  const GLenum primitiveType,
+  const int32_t vertexCount,
+  const meshvertex_t *vertices
+) {
+  assertNotNull(mesh, "Mesh cannot be NULL");
+  assertNotNull(vertices, "Vertices cannot be NULL");
+  assertTrue(vertexCount > 0, "Vertex count must be greater than 0");
+
+  memoryZero(mesh, sizeof(mesh_t));
+  
+  mesh->primitiveType = primitiveType;
+  mesh->vertexCount = vertexCount;
+  mesh->vertices = vertices;
+}
+
+void meshDraw(
+  const mesh_t *mesh,
+  const int32_t vertexOffset,
+  const int32_t vertexCount
+) {
+  const int32_t offset = vertexOffset == -1 ? 0 : vertexOffset;
+  const int32_t count = vertexCount == -1 ? mesh->vertexCount : vertexCount;
+
+  assertNotNull(mesh, "Mesh cannot be NULL");
+  assertTrue(offset >= 0, "Vertex offset must be non-negative");
+  assertTrue(count >= 0, "Vertex count must be non-negative");
+  assertTrue(offset + count <= mesh->vertexCount, 
+    "Vertex offset + count must not exceed vertex count"
+  );
+
+  #if 1
+    // PSP style pointer legacy OpenGL
+    const GLsizei stride = sizeof(meshvertex_t);
+
+    glColorPointer(
+      MESH_VERTEX_COLOR_SIZE,
+      GL_UNSIGNED_BYTE,
+      stride,
+      (const GLvoid*)&mesh->vertices[offset].color[0]
+    );
+    glTexCoordPointer(
+      MESH_VERTEX_UV_SIZE,
+      GL_FLOAT,
+      stride,
+      (const GLvoid*)&mesh->vertices[offset].uv[0]
+    );
+    glVertexPointer(
+      MESH_VERTEX_POS_SIZE,
+      GL_FLOAT,
+      stride,
+      (const GLvoid*)&mesh->vertices[offset].pos[0]
+    );
+    
+    glDrawArrays(
+      mesh->primitiveType,
+      0,
+      count
+    );
+  #else
+    #error "Need to support modern OpenGL with VAOs and VBOs"
+  #endif
+}
+
+void meshDispose(mesh_t *mesh) {
+  assertNotNull(mesh, "Mesh cannot be NULL");
+  memoryZero(mesh, sizeof(mesh_t));
+}