334 lines
8.7 KiB
ReStructuredText
334 lines
8.7 KiB
ReStructuredText
Effects (Shaders)
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=================
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Effects are a single collection of related shaders. They're used for
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easily writing vertex and pixel shaders together all in the same file in
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HLSL format.
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.. code:: cpp
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#include <graphics/graphics.h>
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.. type:: typedef struct gs_effect gs_effect_t
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Effect object.
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.. type:: typedef struct gs_effect_technique gs_technique_t
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Technique object.
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.. type:: typedef struct gs_effect_param gs_eparam_t
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Effect parameter object.
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---------------------
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.. function:: gs_effect_t *gs_effect_create_from_file(const char *file, char **error_string)
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Creates an effect from file.
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:param file: Path to the effect file
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:param error_string: Receives a pointer to the error string, which
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must be freed with :c:func:`bfree()`. If
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*NULL*, this parameter is ignored.
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:return: The effect object, or *NULL* on error
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---------------------
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.. function:: gs_effect_t *gs_effect_create(const char *effect_string, const char *filename, char **error_string)
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Creates an effect from a string.
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:param effect_String: Effect string
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:param error_string: Receives a pointer to the error string, which
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must be freed with :c:func:`bfree()`. If
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*NULL*, this parameter is ignored.
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:return: The effect object, or *NULL* on error
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---------------------
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.. function:: void gs_effect_destroy(gs_effect_t *effect)
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Destroys the effect
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:param effect: Effect object
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---------------------
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.. function:: gs_technique_t *gs_effect_get_technique(const gs_effect_t *effect, const char *name)
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Gets a technique of the effect.
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:param effect: Effect object
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:param name: Name of the technique
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:return: Technique object, or *NULL* if not found
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---------------------
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.. function:: gs_technique_t *gs_effect_get_current_technique(const gs_effect_t *effect)
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Gets the current active technique of the effect.
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:param effect: Effect object
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:return: Technique object, or *NULL* if none currently active
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---------------------
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.. function:: size_t gs_technique_begin(gs_technique_t *technique)
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Begins a technique.
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:param technique: Technique object
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:return: Number of passes this technique uses
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---------------------
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.. function:: void gs_technique_end(gs_technique_t *technique)
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Ends a technique. Make sure all active passes have been ended before
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calling.
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:param technique: Technique object
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---------------------
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.. function:: bool gs_technique_begin_pass(gs_technique_t *technique, size_t pass)
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Begins a pass. Automatically loads the vertex/pixel shaders
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associated with this pass. Draw after calling this function.
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:param technique: Technique object
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:param pass: Pass index
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:return: *true* if the pass is valid, *false* otherwise
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---------------------
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.. function:: bool gs_technique_begin_pass_by_name(gs_technique_t *technique, const char *name)
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Begins a pass by its name if the pass has a name. Automatically
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loads the vertex/pixel shaders associated with this pass. Draw after
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calling this function.
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:param technique: Technique object
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:param name: Name of the pass
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:return: *true* if the pass is valid, *false* otherwise
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---------------------
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.. function:: void gs_technique_end_pass(gs_technique_t *technique)
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Ends a pass.
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:param technique: Technique object
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---------------------
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.. function:: size_t gs_effect_get_num_params(const gs_effect_t *effect)
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Gets the number of parameters associated with the effect.
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:param effect: Effect object
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:return: Number of parameters the effect has
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---------------------
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.. function:: gs_eparam_t *gs_effect_get_param_by_idx(const gs_effect_t *effect, size_t param)
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Gets a parameter of an effect by its index.
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:param effect: Effect object
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:param param: Parameter index
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:return: The effect parameter object, or *NULL* if index
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invalid
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---------------------
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.. function:: gs_eparam_t *gs_effect_get_param_by_name(const gs_effect_t *effect, const char *name)
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Gets parameter of an effect by its name.
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:param effect: Effect object
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:param name: Name of the parameter
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:return: The effect parameter object, or *NULL* if not found
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---------------------
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.. function:: bool gs_effect_loop(gs_effect_t *effect, const char *name)
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Helper function that automatically begins techniques/passes.
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:param effect: Effect object
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:param name: Name of the technique to execute
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:return: *true* to draw, *false* when complete
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Here is an example of how this function is typically used:
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.. code:: cpp
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for (gs_effect_loop(effect, "my_technique")) {
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/* perform drawing here */
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[...]
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}
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---------------------
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.. function:: gs_eparam_t *gs_effect_get_viewproj_matrix(const gs_effect_t *effect)
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Gets the view/projection matrix parameter ("viewproj") of the effect.
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:param effect: Effect object
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:return: The view/projection matrix parameter of the effect
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---------------------
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.. function:: gs_eparam_t *gs_effect_get_world_matrix(const gs_effect_t *effect)
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Gets the world matrix parameter ("world") of the effect.
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:param effect: Effect object
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:return: The world matrix parameter of the effect
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---------------------
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.. function:: void gs_effect_get_param_info(const gs_eparam_t *param, struct gs_effect_param_info *info)
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Gets information about an effect parameter.
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:param param: Effect parameter
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:param info: Pointer to receive the data
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Relevant data types used with this function:
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.. code:: cpp
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enum gs_shader_param_type {
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GS_SHADER_PARAM_UNKNOWN,
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GS_SHADER_PARAM_BOOL,
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GS_SHADER_PARAM_FLOAT,
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GS_SHADER_PARAM_INT,
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GS_SHADER_PARAM_STRING,
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GS_SHADER_PARAM_VEC2,
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GS_SHADER_PARAM_VEC3,
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GS_SHADER_PARAM_VEC4,
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GS_SHADER_PARAM_INT2,
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GS_SHADER_PARAM_INT3,
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GS_SHADER_PARAM_INT4,
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GS_SHADER_PARAM_MATRIX4X4,
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GS_SHADER_PARAM_TEXTURE,
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};
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struct gs_effect_param_info {
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const char *name;
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enum gs_shader_param_type type;
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}
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---------------------
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.. function:: void gs_effect_set_bool(gs_eparam_t *param, bool val)
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Sets a boolean parameter.
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:param param: Effect parameter
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:param val: Boolean value
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---------------------
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.. function:: void gs_effect_set_float(gs_eparam_t *param, float val)
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Sets a floating point parameter.
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:param param: Effect parameter
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:param val: Floating point value
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---------------------
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.. function:: void gs_effect_set_int(gs_eparam_t *param, int val)
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Sets a integer parameter.
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:param param: Effect parameter
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:param val: Integer value
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---------------------
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.. function:: void gs_effect_set_matrix4(gs_eparam_t *param, const struct matrix4 *val)
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Sets a matrix parameter.
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:param param: Effect parameter
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:param val: Matrix
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---------------------
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.. function:: void gs_effect_set_vec2(gs_eparam_t *param, const struct vec2 *val)
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Sets a 2-component vector parameter.
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:param param: Effect parameter
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:param val: Vector
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---------------------
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.. function:: void gs_effect_set_vec3(gs_eparam_t *param, const struct vec3 *val)
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Sets a 3-component vector parameter.
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:param param: Effect parameter
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:param val: Vector
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---------------------
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.. function:: void gs_effect_set_vec4(gs_eparam_t *param, const struct vec4 *val)
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Sets a 4-component vector parameter.
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:param param: Effect parameter
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:param val: Vector
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---------------------
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.. function:: void gs_effect_set_color(gs_eparam_t *param, uint32_t argb)
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Convenience function for setting a color value via an integer value.
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:param param: Effect parameter
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:param argb: Integer color value (i.e. hex value would be
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0xAARRGGBB)
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---------------------
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.. function:: void gs_effect_set_texture(gs_eparam_t *param, gs_texture_t *val)
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Sets a texture parameter.
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:param param: Effect parameter
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:param val: Texture
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---------------------
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.. function:: void gs_effect_set_val(gs_eparam_t *param, const void *val, size_t size)
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Sets a parameter with data manually.
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:param param: Effect parameter
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:param val: Pointer to data
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:param size: Size of data
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---------------------
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.. function:: void gs_effect_set_default(gs_eparam_t *param)
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Sets the parameter to its default value
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:param: Effect parameter
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---------------------
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.. function:: void gs_effect_set_next_sampler(gs_eparam_t *param, gs_samplerstate_t *sampler)
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Manually changes the sampler for an effect parameter the next time
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it's used.
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:param param: Effect parameter
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:param sampler: Sampler state object
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