WIP: Improve texture loading API (continued)

scripts/test-macos-framework.sh

@@ -247,6 +247,7 @@ if [ -n "$PROJECTM_FRAMEWORK" ] && [ -d "$PROJECTM_FRAMEWORK" ]; then
         "memory.h"
         "parameters.h"
         "render_opengl.h"
+        "textures.h"
         "touch.h"
         "types.h"
         "user_sprites.h"

src/api/CMakeLists.txt

@@ -31,6 +31,7 @@ set(PROJECTM_PUBLIC_HEADERS
         "${CMAKE_CURRENT_SOURCE_DIR}/include/projectM-4/parameters.h"
         "${CMAKE_CURRENT_SOURCE_DIR}/include/projectM-4/projectM.h"
         "${CMAKE_CURRENT_SOURCE_DIR}/include/projectM-4/render_opengl.h"
+        "${CMAKE_CURRENT_SOURCE_DIR}/include/projectM-4/textures.h"
         "${CMAKE_CURRENT_SOURCE_DIR}/include/projectM-4/touch.h"
         "${CMAKE_CURRENT_SOURCE_DIR}/include/projectM-4/types.h"
         "${CMAKE_CURRENT_SOURCE_DIR}/include/projectM-4/user_sprites.h"
@@ -79,4 +80,4 @@ if(ENABLE_INSTALL)
             PUBLIC_HEADER DESTINATION "${PROJECTM_INCLUDE_DIR}/projectM-4" COMPONENT Devel
             )
 
-endif()
+endif()

src/api/include/projectM-4/callbacks.h

@@ -88,79 +88,6 @@ PROJECTM_EXPORT void projectm_set_preset_switch_failed_event_callback(projectm_h
                                                                       projectm_preset_switch_failed_event callback,
                                                                       void* user_data);
 
-/**
- * @brief Structure containing texture data returned by the texture load callback.
- *
- * Applications can provide texture data in one of two ways:
- * 1. Raw pixel data: Set data to a valid pointer, width/height to the dimensions,
- *    and channels to the number of color channels (3 for RGB, 4 for RGBA).
- * 2. Existing OpenGL texture: Set texture_id to a valid OpenGL texture ID.
- *
- * If both are provided, the texture_id takes precedence.
- * If neither is provided (data is NULL and texture_id is 0), projectM will
- * attempt to load the texture from the filesystem.
- *
- * @warning When providing a texture_id, projectM takes ownership of the OpenGL texture
- *          and will delete it (via glDeleteTextures) when it is no longer needed. Do not
- *          delete the texture yourself or reuse the texture ID after passing it here.
- *
- * @since 4.2.0
- */
-typedef struct projectm_texture_load_data {
-    const unsigned char* data; /**< Pointer to raw pixel data in standard OpenGL format (first row is bottom of image). Can be NULL. */
-    unsigned int width;        /**< Width of the texture in pixels. Must be > 0 when providing data or texture_id. */
-    unsigned int height;       /**< Height of the texture in pixels. Must be > 0 when providing data or texture_id. */
-    unsigned int channels;     /**< Number of color channels (3 for RGB, 4 for RGBA). */
-    unsigned int texture_id;   /**< An existing OpenGL texture ID to use. Set to 0 if not used. */
-} projectm_texture_load_data;
-
-/**
- * @brief Callback function that is executed when projectM needs to load a texture.
- *
- * This callback allows applications to provide textures from sources other than
- * the filesystem, such as:
- * - Loading textures from archives (e.g., ZIP files)
- * - Loading textures over the network
- * - Generating textures procedurally
- * - Providing pre-loaded textures or video frames
- *
- * When called, the application should populate the provided data structure with
- * either raw pixel data or an OpenGL texture ID. If the application cannot provide
- * the requested texture, it should leave the structure unchanged (data = NULL,
- * texture_id = 0) and projectM will fall back to loading from the filesystem.
- *
- * @note The texture_name pointer is only valid inside the callback. Make a copy if
- *       it needs to be retained for later use.
- * @note If providing raw pixel data, the data pointer must remain valid until
- *       projectM has finished processing it (i.e., until the callback returns).
- * @note This callback is always invoked from the same thread that calls projectM
- *       rendering functions. No additional synchronization is required.
- *
- * @param texture_name The name of the texture being requested, as used in the preset.
- * @param[out] data Pointer to a structure where the application should place texture data.
- * @param user_data A user-defined data pointer that was provided when registering the callback.
- * @since 4.2.0
- */
-typedef void (*projectm_texture_load_event)(const char* texture_name,
-                                            projectm_texture_load_data* data,
-                                            void* user_data);
-
-/**
- * @brief Sets a callback function that will be called when projectM needs to load a texture.
- *
- * This allows applications to provide textures from non-filesystem sources.
- * Only one callback can be registered per projectM instance. To remove the callback, use NULL.
- *
- * @param instance The projectM instance handle.
- * @param callback A pointer to the callback function.
- * @param user_data A pointer to any data that will be sent back in the callback, e.g. context
- *                  information.
- * @since 4.2.0
- */
-PROJECTM_EXPORT void projectm_set_texture_load_event_callback(projectm_handle instance,
-                                                              projectm_texture_load_event callback,
-                                                              void* user_data);
-
 #ifdef __cplusplus
 } // extern "C"
 #endif

src/api/include/projectM-4/projectM.h

@@ -33,6 +33,7 @@
 #include "projectM-4/memory.h"
 #include "projectM-4/parameters.h"
 #include "projectM-4/render_opengl.h"
+#include "projectM-4/textures.h"
 #include "projectM-4/touch.h"
 #include "projectM-4/version.h"
 #include "projectM-4/user_sprites.h"

src/api/include/projectM-4/textures.h

@@ -0,0 +1,203 @@
+/**
+ * @file textures.h
+ * @copyright 2003-2025 projectM Team
+ * @brief Functions, callbacks and prototypes for loading textures.
+ * @since 4.2.0
+ *
+ * projectM -- Milkdrop-esque visualisation SDK
+ * Copyright (C)2003-2024 projectM Team
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * See 'LICENSE.txt' included within this release
+ *
+ */
+
+#pragma once
+
+#include "projectM-4/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Loads a texture from raw, uncompressed pixel data (RGB or RGBA).
+ *
+ * The data buffer must contain at least width * height * channels bytes of pixel data in standard
+ * OpenGL format (first row is the bottom of the image).
+ *
+ * This function can be called at any time to push or pre-load textures, or from within the
+ * texture load event callback.
+ *
+ * @param instance The projectM instance handle.
+ * @param texture_name The unqualified texture name (without wrap/filter prefixes). Case-insensitive.
+ * @param data Pointer to raw pixel data. Must remain valid until this function returns.
+ * @param width Width of the texture in pixels. Must be between 1 and 8192.
+ * @param height Height of the texture in pixels. Must be between 1 and 8192.
+ * @param channels Number of color channels (3 for RGB, 4 for RGBA).
+ * @return true if the texture was loaded successfully, false on error or if a texture with this
+ *         name already exists.
+ * @since 4.2.0
+ */
+PROJECTM_EXPORT bool projectm_texture_load_raw_data(projectm_handle instance,
+                                                     const char* texture_name,
+                                                     const unsigned char* data,
+                                                     unsigned int width,
+                                                     unsigned int height,
+                                                     unsigned int channels);
+
+/**
+ * @brief Loads a texture from an existing OpenGL texture ID.
+ *
+ * projectM will use the texture but will @b not take ownership of it. The application is
+ * responsible for deleting the texture after projectM no longer references it. Use the
+ * texture unload event callback to get notified when the texture is no longer needed.
+ *
+ * This function can be called at any time to push or pre-load textures, or from within the
+ * texture load event callback.
+ *
+ * @param instance The projectM instance handle.
+ * @param texture_name The unqualified texture name (without wrap/filter prefixes). Case-insensitive.
+ * @param texture_id A valid OpenGL texture ID.
+ * @param width Width of the texture in pixels. Must be between 1 and 8192.
+ * @param height Height of the texture in pixels. Must be between 1 and 8192.
+ * @return true if the texture was loaded successfully, false on error or if a texture with this
+ *         name already exists.
+ * @since 4.2.0
+ */
+PROJECTM_EXPORT bool projectm_texture_load_gl_texture(projectm_handle instance,
+                                                       const char* texture_name,
+                                                       unsigned int texture_id,
+                                                       unsigned int width,
+                                                       unsigned int height);
+
+/**
+ * @brief Loads a texture from compressed/encoded image file data.
+ *
+ * Pass the raw contents of a supported image file (e.g. the bytes read from a JPG, PNG, BMP,
+ * TGA, DXT or DDS file) and projectM will decode it internally using stb_image.
+ * GIF and PSD are partially supported.
+ *
+ * This function can be called at any time to push or pre-load textures, or from within the
+ * texture load event callback.
+ *
+ * @param instance The projectM instance handle.
+ * @param texture_name The unqualified texture name (without wrap/filter prefixes). Case-insensitive.
+ * @param data Pointer to the image file contents. Must remain valid until this function returns.
+ * @param data_length Length of the image data buffer in bytes.
+ * @return true if the texture was loaded and decoded successfully, false on error or if a texture
+ *         with this name already exists.
+ * @since 4.2.0
+ */
+PROJECTM_EXPORT bool projectm_texture_load_compressed_image(projectm_handle instance,
+                                                             const char* texture_name,
+                                                             const unsigned char* data,
+                                                             size_t data_length);
+
+/**
+ * @brief Unloads a previously loaded external texture.
+ *
+ * If the texture is currently in use by an active preset, it will remain in memory until the
+ * preset is unloaded. When manually unloading a texture passed by OpenGL ID, the application
+ * should wait one or more preset switches before deleting the actual GL texture to avoid
+ * rendering issues.
+ *
+ * @param instance The projectM instance handle.
+ * @param texture_name The unqualified texture name as used in the load call. Case-insensitive.
+ * @return true if the texture was found and scheduled for removal, false if no texture with the
+ *         given name was found.
+ * @since 4.2.0
+ */
+PROJECTM_EXPORT bool projectm_texture_unload(projectm_handle instance,
+                                              const char* texture_name);
+
+/**
+ * @brief Callback function that is executed when projectM needs to load a texture.
+ *
+ * This callback allows applications to provide textures from sources other than the filesystem,
+ * such as archives, network resources, procedural generators, or pre-loaded data.
+ *
+ * When called, the application should load the requested texture by calling one of the texture
+ * loading functions (@a projectm_texture_load_raw_data, @a projectm_texture_load_gl_texture, or
+ * @a projectm_texture_load_compressed_image) and return true. If the application cannot provide
+ * the requested texture, it should return false and projectM will fall back to loading from
+ * the filesystem.
+ *
+ * @note The texture_name pointer is only valid inside the callback. Make a copy if it needs to
+ *       be retained for later use.
+ * @note This callback is always invoked from the same thread that calls projectM rendering
+ *       functions. No additional synchronization is required.
+ *
+ * @param instance The projectM instance handle. Can be used to call texture loading functions.
+ * @param texture_name The name of the texture being requested, as used in the preset.
+ * @param user_data A user-defined data pointer that was provided when registering the callback.
+ * @return true if the application loaded the texture, false to fall back to filesystem loading.
+ * @since 4.2.0
+ */
+typedef bool (*projectm_texture_load_event)(projectm_handle instance,
+                                            const char* texture_name,
+                                            void* user_data);
+
+/**
+ * @brief Sets a callback function that will be called when projectM needs to load a texture.
+ *
+ * This allows applications to provide textures from non-filesystem sources.
+ * Only one callback can be registered per projectM instance. To remove the callback, use NULL.
+ *
+ * @param instance The projectM instance handle.
+ * @param callback A pointer to the callback function.
+ * @param user_data A pointer to any data that will be sent back in the callback, e.g. context
+ *                  information.
+ * @since 4.2.0
+ */
+PROJECTM_EXPORT void projectm_set_texture_load_event_callback(projectm_handle instance,
+                                                              projectm_texture_load_event callback,
+                                                              void* user_data);
+
+/**
+ * @brief Callback function that will be called after projectM unloads a texture.
+ *
+ * This callback informs the application that a texture with the given name was removed from
+ * projectM's texture manager. This is particularly useful when passing a GL texture ID to
+ * projectM, as it lets the application know when the texture is no longer needed and can be
+ * safely deleted (or at least no longer requires regular updating).
+ *
+ * @note This callback is not fired for textures loaded from the filesystem by projectM itself.
+ *
+ * @param texture_name The name of the texture that was unloaded.
+ * @param user_data A user-defined data pointer that was provided when registering the callback.
+ * @since 4.2.0
+ */
+typedef void (*projectm_texture_unload_event)(const char* texture_name,
+                                              void* user_data);
+
+/**
+ * @brief Sets a callback function that will be called when projectM unloads a texture.
+ *
+ * Only one callback can be registered per projectM instance. To remove the callback, use NULL.
+ *
+ * @param instance The projectM instance handle.
+ * @param callback A pointer to the callback function.
+ * @param user_data A pointer to any data that will be sent back in the callback, e.g. context
+ *                  information.
+ * @since 4.2.0
+ */
+PROJECTM_EXPORT void projectm_set_texture_unload_event_callback(projectm_handle instance,
+                                                                projectm_texture_unload_event callback,
+                                                                void* user_data);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif

src/libprojectM/MilkdropPreset/BlurTexture.cpp

@@ -44,7 +44,7 @@ BlurTexture::BlurTexture()
             textureName = "blur" + std::to_string(i / 2 + 1);
         }
 
-        m_blurTextures[i] = std::make_shared<Renderer::Texture>(textureName, 0, GL_TEXTURE_2D, 0, 0, false);
+        m_blurTextures[i] = std::make_shared<Renderer::Texture>(textureName, 0, GL_TEXTURE_2D, 0, 0, Renderer::Texture::Source::Internal);
     }
 }
 
@@ -370,7 +370,7 @@ void BlurTexture::AllocateTextures(const Renderer::Texture& sourceTexture)
         }
 
         // This will automatically replace any old texture.
-        m_blurTextures[i] = std::make_shared<Renderer::Texture>(textureName, width2, height2, false);
+        m_blurTextures[i] = std::make_shared<Renderer::Texture>(textureName, width2, height2, Renderer::Texture::Source::Internal);
     }
 
     m_sourceTextureWidth = sourceTexture.Width();