libobs, libobs-opengl: Add memory and identification APIs

Add graphics APIs to obtain the GPU driver version and renderer
strings, as well as GDDR memory sizes. The GDDR memory sizes
include the dmem (dedicated memory on the GPU) and smem
(shared CPU memory used by the GPU but resides in the CPU DDR).

The version and renderer strings are needed for identification
purposes, for example enhanced broadcasting used by Twitch, to
associate the GPU used by OBS with the PCIe-based identification
values such as device_id and vendor_id.

libobs-opengl/gl-subsystem.c

@@ -214,6 +214,52 @@ const char *device_preprocessor_name(void)
 	return "_OPENGL";
 }
 
+const char *gpu_get_driver_version(void)
+{
+	return ((const char *)glGetString(GL_VERSION));
+}
+
+const char *gpu_get_renderer(void)
+{
+	return ((const char *)glGetString(GL_RENDERER));
+}
+
+// Get the amount of dedicated GDDR memory, aka VRAM, in units of kilobytes.
+uint64_t gpu_get_dmem(void)
+{
+	GLint dmem = 0;
+	glGetIntegerv(GL_GPU_MEMORY_INFO_DEDICATED_VIDMEM_NVX, &dmem);
+
+	/* GLint is signed, however it makes little sense to have "negative" amounts of GPU memory. Check on this, clamp to
+	 * 0 if so, and cast to an unsigned value explicitly.
+	 */
+	if (dmem < 0) {
+		dmem = 0;
+	}
+
+	return (uint64_t)dmem;
+}
+
+// Get the amount of CPU memory shared by the GPU, in units of kilobytes.
+uint64_t gpu_get_smem(void)
+{
+	GLint dmem, total_mem = 0;
+	glGetIntegerv(GL_GPU_MEMORY_INFO_DEDICATED_VIDMEM_NVX, &dmem);
+	glGetIntegerv(GL_GPU_MEMORY_INFO_TOTAL_AVAILABLE_MEMORY_NVX, &total_mem);
+
+	/* GLint is signed, however it makes little sense to have "negative" amounts of GPU memory. Check on this, clamp to
+	 * 0 if so, and cast to an unsigned value explicitly.
+	 */
+	if (dmem < 0) {
+		dmem = 0;
+	}
+	if (total_mem < 0) {
+		total_mem = 0;
+	}
+
+	return (uint64_t)total_mem - dmem;
+}
+
 int device_create(gs_device_t **p_device, uint32_t adapter)
 {
 	struct gs_device *device = bzalloc(sizeof(struct gs_device));

libobs/graphics/device-exports.h

@@ -24,6 +24,10 @@ extern "C" {
 #endif
 
 EXPORT const char *device_get_name(void);
+EXPORT const char *gpu_get_driver_version(void);
+EXPORT const char *gpu_get_renderer(void);
+EXPORT uint64_t gpu_get_dmem(void);
+EXPORT uint64_t gpu_get_smem(void);
 EXPORT int device_get_type(void);
 EXPORT bool device_enum_adapters(gs_device_t *device, bool (*callback)(void *param, const char *name, uint32_t id),
 				 void *param);

libobs/graphics/graphics-imports.c

@@ -42,6 +42,10 @@ bool load_graphics_imports(struct gs_exports *exports, void *module, const char
 	bool success = true;
 
 	GRAPHICS_IMPORT(device_get_name);
+	GRAPHICS_IMPORT_OPTIONAL(gpu_get_driver_version);
+	GRAPHICS_IMPORT_OPTIONAL(gpu_get_renderer);
+	GRAPHICS_IMPORT_OPTIONAL(gpu_get_dmem);
+	GRAPHICS_IMPORT_OPTIONAL(gpu_get_smem);
 	GRAPHICS_IMPORT(device_get_type);
 	GRAPHICS_IMPORT_OPTIONAL(device_enum_adapters);
 	GRAPHICS_IMPORT(device_preprocessor_name);

libobs/graphics/graphics-internal.h

@@ -25,6 +25,10 @@
 
 struct gs_exports {
 	const char *(*device_get_name)(void);
+	const char *(*gpu_get_driver_version)(void);
+	const char *(*gpu_get_renderer)(void);
+	uint64_t (*gpu_get_dmem)(void);
+	uint64_t (*gpu_get_smem)(void);
 	int (*device_get_type)(void);
 	bool (*device_enum_adapters)(gs_device_t *device, bool (*callback)(void *, const char *, uint32_t), void *);
 	const char *(*device_preprocessor_name)(void);

libobs/graphics/graphics.c

@@ -297,6 +297,26 @@ const char *gs_get_device_name(void)
 	return gs_valid("gs_get_device_name") ? thread_graphics->exports.device_get_name() : NULL;
 }
 
+const char *gs_get_driver_version(void)
+{
+	return gs_valid("gs_get_driver_version") ? thread_graphics->exports.gpu_get_driver_version() : NULL;
+}
+
+const char *gs_get_renderer(void)
+{
+	return gs_valid("gs_get_renderer") ? thread_graphics->exports.gpu_get_renderer() : NULL;
+}
+
+uint64_t gs_get_gpu_dmem(void)
+{
+	return gs_valid("gs_get_gpu_dmem") ? thread_graphics->exports.gpu_get_dmem() : 0;
+}
+
+uint64_t gs_get_gpu_smem(void)
+{
+	return gs_valid("gs_get_gpu_smem") ? thread_graphics->exports.gpu_get_smem() : 0;
+}
+
 int gs_get_device_type(void)
 {
 	return gs_valid("gs_get_device_type") ? thread_graphics->exports.device_get_type() : -1;

libobs/graphics/graphics.h

@@ -502,6 +502,10 @@ struct gs_init_data {
 #define GS_DEVICE_DIRECT3D_11 2
 
 EXPORT const char *gs_get_device_name(void);
+EXPORT const char *gs_get_driver_version(void);
+EXPORT const char *gs_get_renderer(void);
+EXPORT uint64_t gs_get_gpu_dmem(void);
+EXPORT uint64_t gs_get_gpu_smem(void);
 EXPORT int gs_get_device_type(void);
 EXPORT uint32_t gs_get_adapter_count(void);
 EXPORT void gs_enum_adapters(bool (*callback)(void *param, const char *name, uint32_t id), void *param);