Add ability to update texture contents.

4 files changed, 73 insertions, 39 deletions

diff --git a/gfx/include/gfx/render_backend.h b/gfx/include/gfx/render_backend.h
index b07cf16..722ea5e 100644
--- a/gfx/include/gfx/render_backend.h
+++ b/gfx/include/gfx/render_backend.h
@@ -213,8 +213,10 @@ typedef struct ShaderUniform {
   } value;
 } ShaderUniform;
 
+/// Texture dimension.
 typedef enum { Texture2D, TextureCubeMap } TextureDimension;
 
+/// Texture data format.
 typedef enum {
   TextureDepth,
   TextureRG16,
@@ -226,10 +228,13 @@ typedef enum {
   TextureSRGBA8
 } TextureFormat;
 
+/// Texture filtering.
 typedef enum { NearestFiltering, LinearFiltering } TextureFiltering;
 
+/// Texture wrap mode.
 typedef enum { Repeat, ClampToEdge } TextureWrapping;
 
+/// Cubemap faces.
 typedef enum {
   CubemapFacePosX,
   CubemapFaceNegX,
@@ -239,16 +244,8 @@ typedef enum {
   CubemapFaceNegZ
 } CubemapFace;
 
-/// Describes a texture.
-typedef struct TextureDesc {
-  int              width;
-  int              height;
-  int              depth; // Not used until 3D textures are exposed.
-  TextureDimension dimension;
-  TextureFormat    format;
-  TextureFiltering filtering;
-  TextureWrapping  wrap;
-  bool             mipmaps;
+/// Texture data descriptor.
+typedef struct TextureDataDesc {
   union {
     const void* pixels;
     struct {
@@ -260,6 +257,19 @@ typedef struct TextureDesc {
       const void* pixels_neg_z;
     } cubemap;
   };
+} TextureDataDesc;
+
+/// Describes a texture.
+typedef struct TextureDesc {
+  int              width;
+  int              height;
+  int              depth; // Not used until 3D textures are exposed.
+  TextureDimension dimension;
+  TextureFormat    format;
+  TextureFiltering filtering;
+  TextureWrapping  wrap;
+  bool             mipmaps;
+  TextureDataDesc  data;
 } TextureDesc;
 
 /// Describes a renderbuffer.
@@ -339,7 +349,7 @@ Buffer* gfx_make_buffer(RenderBackend*, const BufferDesc*);
 void gfx_destroy_buffer(RenderBackend*, Buffer**);
 
 /// Update the buffer's data.
-void gfx_update_buffer(RenderBackend*, Buffer*, const BufferDataDesc*);
+void gfx_update_buffer(Buffer*, const BufferDataDesc*);
 
 // -----------------------------------------------------------------------------
 // Geometry.
@@ -385,6 +395,9 @@ Texture* gfx_make_texture(RenderBackend*, const TextureDesc*);
 /// Destroy the texture.
 void gfx_destroy_texture(RenderBackend*, Texture**);
 
+/// Update the texture.
+void gfx_update_texture(Texture*, const TextureDataDesc*);
+
 // -----------------------------------------------------------------------------
 // Renderbuffers.
 // -----------------------------------------------------------------------------
diff --git a/gfx/src/render/texture.c b/gfx/src/render/texture.c
index 312aecc..489f7a2 100644
--- a/gfx/src/render/texture.c
+++ b/gfx/src/render/texture.c
@@ -37,32 +37,14 @@ bool gfx_init_texture(Texture* texture, const TextureDesc* desc) {
     return false;
   }
 
-  // glTexSubImageXD
-  const GLenum format = to_GL_format(desc->format);
-  const GLenum type   = to_GL_type(desc->format);
-  switch (texture->target) {
-  case GL_TEXTURE_2D:
-    if (desc->pixels) {
-      glTexSubImage2D(
-          GL_TEXTURE_2D, /*level=*/0, /*xoffset=*/0,
-          /*yoffset=*/0, desc->width, desc->height, format, type, desc->pixels);
-    }
-    break;
-  case GL_TEXTURE_CUBE_MAP:
-    for (int i = 0; i < 6; ++i) {
-      const void* pixels = *(&desc->cubemap.pixels_pos_x + i);
-      if (pixels) {
-        glTexSubImage2D(
-            GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, /*level=*/0, /*xoffset=*/0,
-            /*yoffset=*/0, desc->width, desc->height, format, type, pixels);
-      }
-    }
-    break;
-  default:
-    assert(false && "Unhandled texture dimension");
-    gfx_del_texture(texture);
-    return false;
-  }
+  texture->format = to_GL_format(desc->format);
+  texture->type   = to_GL_type(desc->format);
+  texture->width  = desc->width;
+  texture->height = desc->height;
+  gfx_update_texture(texture, &desc->data);
+
+  // gfx_update_texture() unbinds the texture at the end, so re-bind it here.
+  glBindTexture(texture->target, texture->id);
 
   // Mipmaps.
   if (desc->mipmaps) {
@@ -103,6 +85,41 @@ void gfx_del_texture(Texture* texture) {
   }
 }
 
+void gfx_update_texture(Texture* texture, const TextureDataDesc* desc) {
+  assert(texture);
+  assert(desc);
+
+  glBindTexture(texture->target, texture->id);
+
+  // glTexSubImageXD
+  switch (texture->target) {
+  case GL_TEXTURE_2D:
+    if (desc->pixels) {
+      glTexSubImage2D(
+          GL_TEXTURE_2D, /*level=*/0, /*xoffset=*/0,
+          /*yoffset=*/0, texture->width, texture->height, texture->format,
+          texture->type, desc->pixels);
+    }
+    break;
+  case GL_TEXTURE_CUBE_MAP:
+    for (int i = 0; i < 6; ++i) {
+      const void* pixels = *(&desc->cubemap.pixels_pos_x + i);
+      if (pixels) {
+        glTexSubImage2D(
+            GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, /*level=*/0, /*xoffset=*/0,
+            /*yoffset=*/0, texture->width, texture->height, texture->format,
+            texture->type, pixels);
+      }
+    }
+    break;
+  default:
+    assert(false && "Unhandled texture dimension");
+    break;
+  }
+
+  glBindTexture(texture->target, 0);
+}
+
 GLenum to_GL_dimension(TextureDimension dim) {
   switch (dim) {
   case Texture2D:
diff --git a/gfx/src/render/texture.h b/gfx/src/render/texture.h
index b4e4bed..f667752 100644
--- a/gfx/src/render/texture.h
+++ b/gfx/src/render/texture.h
@@ -7,6 +7,10 @@
 typedef struct Texture {
   GLuint id;
   GLenum target;
+  GLenum format;
+  GLenum type;
+  int    width;
+  int    height;
 } Texture;
 
 /// Create a new texture.
diff --git a/gfx/src/util/texture.c b/gfx/src/util/texture.c
index 7ec0e40..23f15f0 100644
--- a/gfx/src/util/texture.c
+++ b/gfx/src/util/texture.c
@@ -159,11 +159,11 @@ Texture* gfx_load_texture(
 
   switch (cmd->type) {
   case LoadTexture:
-    desc.pixels = pixels[0];
+    desc.data.pixels = pixels[0];
     break;
   case LoadCubemap:
     for (int i = 0; i < 6; ++i) {
-      *(&desc.cubemap.pixels_pos_x + i) = pixels[i];
+      *(&desc.data.cubemap.pixels_pos_x + i) = pixels[i];
     }
     break;
   }