OBS图形及渲染
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obs_init_graphics
OBS立即顶点坐标vb

obs_init_graphics之gs_create

2024-04-26 54 0

gs_create函数实现功能如下：

  • 1.os_dlopen加载对应的DLL导内存，即LoadLibray
  • 2.GetProcessAddress获取所有导出函数指针
  • 3.调用device_create函数，模块内部初始化
  • 4.graphics_init OBS渲染用到的资源初始化
int gs_create(graphics_t **pgraphics, const char *module, uint32_t adapter)
{
    int errcode = GS_ERROR_FAIL;

    graphics_t *graphics = bzalloc(sizeof(struct graphics_subsystem));
    pthread_mutex_init_value(&graphics->mutex);
    pthread_mutex_init_value(&graphics->effect_mutex);

    //Loadlibray
    graphics->module = os_dlopen(module);
    if (!graphics->module) {
        errcode = GS_ERROR_MODULE_NOT_FOUND;
        goto error;
    }

    //2.GetProcessAddress
    if (!load_graphics_imports(&graphics->exports, graphics->module, module))
        goto error;

    //调用d3d11的device_create函数，模块内部初始化
    errcode = graphics->exports.device_create(&graphics->device, adapter);
    if (errcode != GS_SUCCESS)
        goto error;

    //其它资源初始化
    if (!graphics_init(graphics)) {
        errcode = GS_ERROR_FAIL;
        goto error;
    }

    *pgraphics = graphics;
    return errcode;

error:
    gs_destroy(graphics);
    return errcode;
}

graphics_t结构体

typedef struct graphics_subsystem graphics_t;

重新typedef了，不要被名不同而误导。

struct graphics_subsystem {
    void *module;
    gs_device_t *device;  //d3d11相关
    struct gs_exports exports;  //导出函数集

    DARRAY(struct gs_rect) viewport_stack;

    DARRAY(struct matrix4) matrix_stack;
    size_t cur_matrix;

    struct matrix4 projection;
    struct gs_effect *cur_effect;

    gs_vertbuffer_t *sprite_buffer;

    bool using_immediate;
    struct gs_vb_data *vbd;
    gs_vertbuffer_t *immediate_vertbuffer;
    DARRAY(struct vec3) verts;
    DARRAY(struct vec3) norms;
    DARRAY(uint32_t) colors;
    DARRAY(struct vec2) texverts[16];

    pthread_mutex_t effect_mutex;
    struct gs_effect *first_effect;

    pthread_mutex_t mutex;
    volatile long ref;

    struct blend_state cur_blend_state;
    DARRAY(struct blend_state) blend_state_stack;

    bool linear_srgb;
};

DLL导出函数

OBS的核心结构模块图如下：
144537679791
从上图可知，其导出的DLL函数保存在graphics->exports结构体中。

其关于视频处理的参数及函数都是由struct obs_core_video video成员来保存。而对于图形处理由是由统一的graphcis.c来实现，其根据struct obs_video_info ovi;传递的模块名加载不同的dll,可以是opengl的，也可以是d3d11的。

这其中关于graphics.h导出的函数包括有：

#define GRAPHICS_IMPORT(func)                                     \
    do {                                                      \
        exports->func = os_dlsym(module, #func);          \
        if (!exports->func) {                             \
            success = false;                          \
            blog(LOG_ERROR,                           \
                 "Could not load function '%s' from " \
                 "module '%s'",                       \
                 #func, module_name);                 \
        }                                                 \
    } while (false)

#define GRAPHICS_IMPORT_OPTIONAL(func)                   \
    do {                                             \
        exports->func = os_dlsym(module, #func); \
    } while (false)

bool load_graphics_imports(struct gs_exports *exports, void *module,
               const char *module_name)
{
    bool success = true;

    GRAPHICS_IMPORT(device_get_name);
    GRAPHICS_IMPORT(device_get_type);
    GRAPHICS_IMPORT_OPTIONAL(device_enum_adapters);
    GRAPHICS_IMPORT(device_preprocessor_name);
    GRAPHICS_IMPORT(device_create);
    GRAPHICS_IMPORT(device_destroy);
    GRAPHICS_IMPORT(device_enter_context);
    GRAPHICS_IMPORT(device_leave_context);
    GRAPHICS_IMPORT(device_get_device_obj);
    GRAPHICS_IMPORT(device_swapchain_create);
    GRAPHICS_IMPORT(device_resize);
    GRAPHICS_IMPORT(device_get_color_space);
    GRAPHICS_IMPORT(device_update_color_space);
    GRAPHICS_IMPORT(device_get_size);
    GRAPHICS_IMPORT(device_get_width);
    GRAPHICS_IMPORT(device_get_height);
    GRAPHICS_IMPORT(device_texture_create);
    GRAPHICS_IMPORT(device_cubetexture_create);
    GRAPHICS_IMPORT(device_voltexture_create);
    GRAPHICS_IMPORT(device_zstencil_create);
    GRAPHICS_IMPORT(device_stagesurface_create);
    GRAPHICS_IMPORT(device_samplerstate_create);
    GRAPHICS_IMPORT(device_vertexshader_create);
    GRAPHICS_IMPORT(device_pixelshader_create);
    GRAPHICS_IMPORT(device_vertexbuffer_create);
    GRAPHICS_IMPORT(device_indexbuffer_create);
    GRAPHICS_IMPORT(device_timer_create);
    GRAPHICS_IMPORT(device_timer_range_create);
    GRAPHICS_IMPORT(device_get_texture_type);
    GRAPHICS_IMPORT(device_load_vertexbuffer);
    GRAPHICS_IMPORT(device_load_indexbuffer);
    GRAPHICS_IMPORT(device_load_texture);
    GRAPHICS_IMPORT(device_load_samplerstate);
    GRAPHICS_IMPORT(device_load_vertexshader);
    GRAPHICS_IMPORT(device_load_pixelshader);
    GRAPHICS_IMPORT(device_load_default_samplerstate);
    GRAPHICS_IMPORT(device_get_vertex_shader);
    GRAPHICS_IMPORT(device_get_pixel_shader);
    GRAPHICS_IMPORT(device_get_render_target);
    GRAPHICS_IMPORT(device_get_zstencil_target);
    GRAPHICS_IMPORT(device_set_render_target);
    GRAPHICS_IMPORT(device_set_render_target_with_color_space);
    GRAPHICS_IMPORT(device_set_cube_render_target);
    GRAPHICS_IMPORT(device_enable_framebuffer_srgb);
    GRAPHICS_IMPORT(device_framebuffer_srgb_enabled);
    GRAPHICS_IMPORT(device_copy_texture_region);
    GRAPHICS_IMPORT(device_copy_texture);
    GRAPHICS_IMPORT(device_stage_texture);
    GRAPHICS_IMPORT(device_begin_frame);
    GRAPHICS_IMPORT(device_begin_scene);
    GRAPHICS_IMPORT(device_draw);
    GRAPHICS_IMPORT(device_load_swapchain);
    GRAPHICS_IMPORT(device_end_scene);
    GRAPHICS_IMPORT(device_clear);
    GRAPHICS_IMPORT(device_is_present_ready);
    GRAPHICS_IMPORT(device_present);
    GRAPHICS_IMPORT(device_flush);
    GRAPHICS_IMPORT(device_set_cull_mode);
    GRAPHICS_IMPORT(device_get_cull_mode);
    GRAPHICS_IMPORT(device_enable_blending);
    GRAPHICS_IMPORT(device_enable_depth_test);
    GRAPHICS_IMPORT(device_enable_stencil_test);
    GRAPHICS_IMPORT(device_enable_stencil_write);
    GRAPHICS_IMPORT(device_enable_color);
    GRAPHICS_IMPORT(device_blend_function);
    GRAPHICS_IMPORT(device_blend_function_separate);
    GRAPHICS_IMPORT(device_blend_op);
    GRAPHICS_IMPORT(device_depth_function);
    GRAPHICS_IMPORT(device_stencil_function);
    GRAPHICS_IMPORT(device_stencil_op);
    GRAPHICS_IMPORT(device_set_viewport);
    GRAPHICS_IMPORT(device_get_viewport);
    GRAPHICS_IMPORT(device_set_scissor_rect);
    GRAPHICS_IMPORT(device_ortho);
    GRAPHICS_IMPORT(device_frustum);
    GRAPHICS_IMPORT(device_projection_push);
    GRAPHICS_IMPORT(device_projection_pop);

    GRAPHICS_IMPORT(gs_swapchain_destroy);

    GRAPHICS_IMPORT(gs_texture_destroy);
    GRAPHICS_IMPORT(gs_texture_get_width);
    GRAPHICS_IMPORT(gs_texture_get_height);
    GRAPHICS_IMPORT(gs_texture_get_color_format);
    GRAPHICS_IMPORT(gs_texture_map);
    GRAPHICS_IMPORT(gs_texture_unmap);
    GRAPHICS_IMPORT_OPTIONAL(gs_texture_is_rect);
    GRAPHICS_IMPORT(gs_texture_get_obj);

    GRAPHICS_IMPORT(gs_cubetexture_destroy);
    GRAPHICS_IMPORT(gs_cubetexture_get_size);
    GRAPHICS_IMPORT(gs_cubetexture_get_color_format);

    GRAPHICS_IMPORT(gs_voltexture_destroy);
    GRAPHICS_IMPORT(gs_voltexture_get_width);
    GRAPHICS_IMPORT(gs_voltexture_get_height);
    GRAPHICS_IMPORT(gs_voltexture_get_depth);
    GRAPHICS_IMPORT(gs_voltexture_get_color_format);

    GRAPHICS_IMPORT(gs_stagesurface_destroy);
    GRAPHICS_IMPORT(gs_stagesurface_get_width);
    GRAPHICS_IMPORT(gs_stagesurface_get_height);
    GRAPHICS_IMPORT(gs_stagesurface_get_color_format);
    GRAPHICS_IMPORT(gs_stagesurface_map);
    GRAPHICS_IMPORT(gs_stagesurface_unmap);

    GRAPHICS_IMPORT(gs_zstencil_destroy);

    GRAPHICS_IMPORT(gs_samplerstate_destroy);

    GRAPHICS_IMPORT(gs_vertexbuffer_destroy);
    GRAPHICS_IMPORT(gs_vertexbuffer_flush);
    GRAPHICS_IMPORT(gs_vertexbuffer_flush_direct);
    GRAPHICS_IMPORT(gs_vertexbuffer_get_data);

    GRAPHICS_IMPORT(gs_indexbuffer_destroy);
    GRAPHICS_IMPORT(gs_indexbuffer_flush);
    GRAPHICS_IMPORT(gs_indexbuffer_flush_direct);
    GRAPHICS_IMPORT(gs_indexbuffer_get_data);
    GRAPHICS_IMPORT(gs_indexbuffer_get_num_indices);
    GRAPHICS_IMPORT(gs_indexbuffer_get_type);

    GRAPHICS_IMPORT(gs_timer_destroy);
    GRAPHICS_IMPORT(gs_timer_begin);
    GRAPHICS_IMPORT(gs_timer_end);
    GRAPHICS_IMPORT(gs_timer_get_data);
    GRAPHICS_IMPORT(gs_timer_range_destroy);
    GRAPHICS_IMPORT(gs_timer_range_begin);
    GRAPHICS_IMPORT(gs_timer_range_end);
    GRAPHICS_IMPORT(gs_timer_range_get_data);

    GRAPHICS_IMPORT(gs_shader_destroy);
    GRAPHICS_IMPORT(gs_shader_get_num_params);
    GRAPHICS_IMPORT(gs_shader_get_param_by_idx);
    GRAPHICS_IMPORT(gs_shader_get_param_by_name);
    GRAPHICS_IMPORT(gs_shader_get_viewproj_matrix);
    GRAPHICS_IMPORT(gs_shader_get_world_matrix);
    GRAPHICS_IMPORT(gs_shader_get_param_info);
    GRAPHICS_IMPORT(gs_shader_set_bool);
    GRAPHICS_IMPORT(gs_shader_set_float);
    GRAPHICS_IMPORT(gs_shader_set_int);
    GRAPHICS_IMPORT(gs_shader_set_matrix3);
    GRAPHICS_IMPORT(gs_shader_set_matrix4);
    GRAPHICS_IMPORT(gs_shader_set_vec2);
    GRAPHICS_IMPORT(gs_shader_set_vec3);
    GRAPHICS_IMPORT(gs_shader_set_vec4);
    GRAPHICS_IMPORT(gs_shader_set_texture);
    GRAPHICS_IMPORT(gs_shader_set_val);
    GRAPHICS_IMPORT(gs_shader_set_default);
    GRAPHICS_IMPORT(gs_shader_set_next_sampler);

    GRAPHICS_IMPORT_OPTIONAL(device_nv12_available);
    GRAPHICS_IMPORT_OPTIONAL(device_p010_available);
    GRAPHICS_IMPORT_OPTIONAL(device_texture_create_nv12);
    GRAPHICS_IMPORT_OPTIONAL(device_texture_create_p010);

    GRAPHICS_IMPORT(device_is_monitor_hdr);

    GRAPHICS_IMPORT(device_debug_marker_begin);
    GRAPHICS_IMPORT(device_debug_marker_end);

    GRAPHICS_IMPORT_OPTIONAL(gs_get_adapter_count);

    /* OSX/Cocoa specific functions */
#ifdef __APPLE__
    GRAPHICS_IMPORT(device_shared_texture_available);
    GRAPHICS_IMPORT(device_texture_open_shared);
    GRAPHICS_IMPORT(device_texture_create_from_iosurface);
    GRAPHICS_IMPORT(gs_texture_rebind_iosurface);

    /* win32 specific functions */
#elif _WIN32
    GRAPHICS_IMPORT(device_gdi_texture_available);
    GRAPHICS_IMPORT(device_shared_texture_available);
    GRAPHICS_IMPORT_OPTIONAL(device_get_duplicator_monitor_info);
    GRAPHICS_IMPORT_OPTIONAL(device_duplicator_get_monitor_index);
    GRAPHICS_IMPORT_OPTIONAL(device_duplicator_create);
    GRAPHICS_IMPORT_OPTIONAL(gs_duplicator_destroy);
    GRAPHICS_IMPORT_OPTIONAL(gs_duplicator_update_frame);
    GRAPHICS_IMPORT_OPTIONAL(gs_duplicator_get_texture);
    GRAPHICS_IMPORT_OPTIONAL(gs_duplicator_get_color_space);
    GRAPHICS_IMPORT_OPTIONAL(gs_duplicator_get_sdr_white_level);
    GRAPHICS_IMPORT_OPTIONAL(device_can_adapter_fast_clear);
    GRAPHICS_IMPORT_OPTIONAL(device_texture_create_gdi);
    GRAPHICS_IMPORT_OPTIONAL(gs_texture_get_dc);
    GRAPHICS_IMPORT_OPTIONAL(gs_texture_release_dc);
    GRAPHICS_IMPORT_OPTIONAL(device_texture_open_shared);
    GRAPHICS_IMPORT_OPTIONAL(device_texture_open_nt_shared);
    GRAPHICS_IMPORT_OPTIONAL(device_texture_get_shared_handle);
    GRAPHICS_IMPORT_OPTIONAL(device_texture_wrap_obj);
    GRAPHICS_IMPORT_OPTIONAL(device_texture_acquire_sync);
    GRAPHICS_IMPORT_OPTIONAL(device_texture_release_sync);
    GRAPHICS_IMPORT_OPTIONAL(device_stagesurface_create_nv12);
    GRAPHICS_IMPORT_OPTIONAL(device_stagesurface_create_p010);
    GRAPHICS_IMPORT_OPTIONAL(device_register_loss_callbacks);
    GRAPHICS_IMPORT_OPTIONAL(device_unregister_loss_callbacks);
#elif defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
    GRAPHICS_IMPORT(device_texture_create_from_dmabuf);
    GRAPHICS_IMPORT(device_query_dmabuf_capabilities);
    GRAPHICS_IMPORT(device_query_dmabuf_modifiers_for_format);
    GRAPHICS_IMPORT(device_texture_create_from_pixmap);
#endif

    return success;
}

device_create回调

d3d11的device_create函数如下：

int device_create(gs_device_t **p_device, uint32_t adapter)
{
    gs_device *device = NULL;
    int errorcode = GS_SUCCESS;

    try {
        //打印所有显卡及该显卡下的显示器信息
        LogD3DAdapters();

        //创建obs-studio/shader-cache 目录
        CreateShaderCacheDirectory();

        device = new gs_device(adapter);

    } catch (const UnsupportedHWError &error) {
        blog(LOG_ERROR, "device_create (D3D11): %s (%08lX)", error.str,  error.hr);
        errorcode = GS_ERROR_NOT_SUPPORTED;

    } catch (const HRError &error) {
        blog(LOG_ERROR, "device_create (D3D11): %s (%08lX)", error.str,error.hr);
        errorcode = GS_ERROR_FAIL;
    }

    *p_device = device;
    return errorcode;
}

然后最重析的就是创建gs_device结构体的new了。gs_device描述符obs对d3d11和opengl的设备对象抽象。其中使用那个显卡，由adapter即obs_video_info成员的 ovi.adapter决定。一般为0。

gs_device结构体构造函数的初始化如下：

gs_device::gs_device(uint32_t adapterIdx)
    : curToplogy(D3D11_PRIMITIVE_TOPOLOGY_UNDEFINED)
{
    matrix4_identity(&curProjMatrix);
    matrix4_identity(&curViewMatrix);
    matrix4_identity(&curViewProjMatrix);

    memset(&viewport, 0, sizeof(viewport));

    for (size_t i = 0; i < GS_MAX_TEXTURES; i++)
    {
        curTextures[i] = NULL;
        curSamplers[i] = NULL;
    }

    InitFactory();
    InitAdapter(adapterIdx);

    //初始化D3D11Device和D3D11DeviceContext
    InitDevice(adapterIdx);

    //渲染目标相关，如到窗口选择交换链
    device_set_render_target(this, NULL, NULL);
}

graphics_init

graphics_init是OBS资源初始化。

static bool graphics_init(struct graphics_subsystem *graphics)
{
    struct matrix4 top_mat;

    matrix4_identity(&top_mat);
    da_push_back(graphics->matrix_stack, &top_mat);

//do nothing
    graphics->exports.device_enter_context(graphics->device);

    //初始   gs_vertbuffer_t *immediate_vertbuffer
    if (!graphics_init_immediate_vb(graphics))
        return false;

    //初始化 gs_vertbuffer_t *sprite_buffer
    if (!graphics_init_sprite_vb(graphics))
        return false;


    if (pthread_mutex_init(&graphics->mutex, NULL) != 0)
        return false;
    if (pthread_mutex_init(&graphics->effect_mutex, NULL) != 0)
        return false;

    //好像只有OPENGL用到
    graphics->exports.device_blend_function_separate(graphics->device, GS_BLEND_SRCALPHA, GS_BLEND_INVSRCALPHA,GS_BLEND_ONE, GS_BLEND_INVSRCALPHA);

    //当前的混合状态
    graphics->cur_blend_state.enabled = true;
    graphics->cur_blend_state.src_c = GS_BLEND_SRCALPHA;
    graphics->cur_blend_state.dest_c = GS_BLEND_INVSRCALPHA;
    graphics->cur_blend_state.src_a = GS_BLEND_ONE;
    graphics->cur_blend_state.dest_a = GS_BLEND_INVSRCALPHA;
    graphics->cur_blend_state.op = GS_BLEND_OP_ADD;
    graphics->exports.device_blend_op(graphics->device, graphics->cur_blend_state.op);

    graphics->exports.device_leave_context(graphics->device);

    //空
    gs_init_image_deps();
    return true;
}

而graphics_init_immediate_vb和graphics_init_sprite_vb则分别创建其对应的顶点坐标和纹理，不过数量等有所差异。

static bool graphics_init_immediate_vb(struct graphics_subsystem *graphics)
{
    struct gs_vb_data *vbd;

    vbd = gs_vbdata_create();

    //512个顶 点、法线、颜色
    vbd->num = IMMEDIATE_COUNT;//512
    vbd->points = bmalloc(sizeof(struct vec3) * IMMEDIATE_COUNT);
    vbd->normals = bmalloc(sizeof(struct vec3) * IMMEDIATE_COUNT);
    vbd->colors = bmalloc(sizeof(uint32_t) * IMMEDIATE_COUNT);

    //1个纹理
    vbd->num_tex = 1;
    vbd->tvarray = bmalloc(sizeof(struct gs_tvertarray));
    vbd->tvarray[0].width = 2;
    vbd->tvarray[0].array = bmalloc(sizeof(struct vec2) * IMMEDIATE_COUNT);

    graphics->immediate_vertbuffer =graphics->exports.device_vertexbuffer_create(graphics->device, vbd, GS_DYNAMIC);
    if (!graphics->immediate_vertbuffer)
        return false;

    return true;
}

static bool graphics_init_sprite_vb(struct graphics_subsystem *graphics)
{
    struct gs_vb_data *vbd;

    vbd = gs_vbdata_create();

    //4个顶点
    vbd->num = 4;
    vbd->points = bmalloc(sizeof(struct vec3) * 4);

    //1个纹理
    vbd->num_tex = 1;
    vbd->tvarray = bmalloc(sizeof(struct gs_tvertarray));
    vbd->tvarray[0].width = 2;
    vbd->tvarray[0].array = bmalloc(sizeof(struct vec2) * 4);

    memset(vbd->points, 0, sizeof(struct vec3) * 4);
    memset(vbd->tvarray[0].array, 0, sizeof(struct vec2) * 4);

    graphics->sprite_buffer = graphics->exports.device_vertexbuffer_create(graphics->device, vbd, GS_DYNAMIC);
    if (!graphics->sprite_buffer)
        return false;

    return true;
}
obs_init_graphics
OBS立即顶点坐标vb

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作者信息
我爱内核
Windows驱动开发，网站开发
好好学习，天天向上。
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