mutter/cogl/cogl-depth-state.h

262 lines
8.0 KiB
C
Raw Normal View History

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2011 Intel Corporation.
*
* 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 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, see
* <http://www.gnu.org/licenses/>.
*
* Authors:
* Robert Bragg <robert@linux.intel.com>
*
*/
#if !defined(__COGL_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
#error "Only <cogl/cogl.h> can be included directly."
#endif
#ifndef __COGL_DEPTH_STATE_H__
#define __COGL_DEPTH_STATE_H__
G_BEGIN_DECLS
/**
* SECTION:cogl-depth-state
* @short_description: Functions for describing the depth testing
* state of your GPU.
*/
typedef struct
{
guint32 COGL_PRIVATE (magic);
gboolean COGL_PRIVATE (test_enabled);
CoglDepthTestFunction COGL_PRIVATE (test_function);
gboolean COGL_PRIVATE (write_enabled);
float COGL_PRIVATE (range_near);
float COGL_PRIVATE (range_far);
guint32 COGL_PRIVATE (padding0);
guint32 COGL_PRIVATE (padding1);
guint32 COGL_PRIVATE (padding2);
guint32 COGL_PRIVATE (padding3);
guint32 COGL_PRIVATE (padding4);
guint32 COGL_PRIVATE (padding5);
guint32 COGL_PRIVATE (padding6);
guint32 COGL_PRIVATE (padding7);
guint32 COGL_PRIVATE (padding8);
guint32 COGL_PRIVATE (padding9);
} CoglDepthState;
/**
* cogl_depth_state_init:
* @state: A #CoglDepthState struct
*
* Initializes the members of @state to their default values.
*
* You should never pass an un initialized #CoglDepthState structure
* to cogl_pipeline_set_depth_state().
*
* Since: 2.0
* Stability: Unstable
*/
void
cogl_depth_state_init (CoglDepthState *state);
/**
* cogl_depth_state_set_test_enabled:
* @state: A #CoglDepthState struct
* @enable: The enable state you want
*
* Enables or disables depth testing according to the value of
* @enable.
*
* If depth testing is enable then the #CoglDepthTestFunction set
* using cogl_pipeline_set_depth_test_function() us used to evaluate
* the depth value of incoming fragments against the corresponding
* value stored in the current depth buffer, and if the test passes
* then the fragments depth value is used to update the depth buffer.
* (unless you have disabled depth writing via
* cogl_pipeline_set_depth_writing_enabled ())
*
* By default depth testing is disabled.
*
* NB: this won't directly affect the state of the GPU. You have
* to then set the state on a #CoglPipeline using
* cogl_pipeline_set_depth_state()
*
* Since: 2.0
* Stability: Unstable
*/
void
cogl_depth_state_set_test_enabled (CoglDepthState *state,
gboolean enable);
/**
* cogl_depth_state_get_test_enabled:
* @state: A #CoglDepthState struct
*
* Gets the current depth test enabled state as previously set by
* cogl_depth_state_set_test_enabled().
*
* Returns: The pipeline's current depth test enabled state.
* Since: 2.0
* Stability: Unstable
*/
gboolean
cogl_depth_state_get_test_enabled (CoglDepthState *state);
/**
* cogl_depth_state_set_write_enabled:
* @state: A #CoglDepthState struct
* @enable: The enable state you want
*
* Enables or disables depth buffer writing according to the value of
* @enable. Normally when depth testing is enabled and the comparison
* between a fragment's depth value and the corresponding depth buffer
* value passes then the fragment's depth is written to the depth
* buffer unless writing is disabled here.
*
* By default depth writing is enabled
*
* NB: this won't directly affect the state of the GPU. You have
* to then set the state on a #CoglPipeline using
* cogl_pipeline_set_depth_state()
*
* Since: 2.0
* Stability: Unstable
*/
void
cogl_depth_state_set_write_enabled (CoglDepthState *state,
gboolean enable);
/**
* cogl_depth_state_get_write_enabled:
* @state: A #CoglDepthState struct
*
* Gets the depth writing enable state as set by the corresponding
* cogl_pipeline_set_depth_writing_enabled.
*
* Returns: The current depth writing enable state
* Since: 2.0
* Stability: Unstable
*/
gboolean
cogl_depth_state_get_write_enabled (CoglDepthState *state);
/**
* cogl_depth_state_set_test_function:
* @state: A #CoglDepthState struct
* @function: The #CoglDepthTestFunction to set
*
* Sets the #CoglDepthTestFunction used to compare the depth value of
* an incoming fragment against the corresponding value in the current
* depth buffer.
*
* By default the depth test function is %COGL_DEPTH_TEST_FUNCTION_LESS
*
* NB: this won't directly affect the state of the GPU. You have
* to then set the state on a #CoglPipeline using
* cogl_pipeline_set_depth_state()
*
* Since: 2.0
* Stability: Unstable
*/
void
cogl_depth_state_set_test_function (CoglDepthState *state,
CoglDepthTestFunction function);
/**
* cogl_depth_state_get_test_function:
* @state: A #CoglDepthState struct
*
* Gets the current depth test enable state as previously set via
* cogl_pipeline_set_depth_test_enabled().
*
* Returns: The current depth test enable state.
* Since: 2.0
* Stability: Unstable
*/
CoglDepthTestFunction
cogl_depth_state_get_test_function (CoglDepthState *state);
/**
* cogl_depth_state_set_range:
* @state: A #CoglDepthState object
* @near_val: The near component of the desired depth range which will be
* clamped to the range [0, 1]
* @far_val: The far component of the desired depth range which will be
* clamped to the range [0, 1]
* @error: location to store an error of type #CoglError
*
* Sets the range to map depth values in normalized device coordinates
* to before writing out to a depth buffer.
*
* After your geometry has be transformed, clipped and had perspective
* division applied placing it in normalized device
* coordinates all depth values between the near and far z clipping
* planes are in the range -1 to 1. Before writing any depth value to
* the depth buffer though the value is mapped into the range [0, 1].
*
* With this function you can change the range which depth values are
* mapped too although the range must still lye within the range [0,
* 1].
*
* If your driver does not support this feature (for example you are
* using GLES 1 drivers) then if you don't use the default range
* values you will get an error reported when calling
* cogl_pipeline_set_depth_state (). You can check ahead of time for
* the %COGL_FEATURE_DEPTH_RANGE feature with
* cogl_features_available() to know if this function will succeed.
*
* By default normalized device coordinate depth values are mapped to
* the full range of depth buffer values, [0, 1].
*
* NB: this won't directly affect the state of the GPU. You have
* to then set the state on a #CoglPipeline using
* cogl_pipeline_set_depth_state().
*
* Since: 2.0
* Stability: Unstable
*/
void
cogl_depth_state_set_range (CoglDepthState *state,
float near_val,
float far_val);
/**
* cogl_depth_state_get_range:
* @pipeline: A #CoglPipeline object
* @near_val: A pointer to store the near component of the depth range
* @far_val: A pointer to store the far component of the depth range
*
* Gets the current range to which normalized depth values are mapped
* before writing to the depth buffer. This corresponds to the range
* set with cogl_pipeline_set_depth_range().
*
* Since: 2.0
* Stability: Unstable
*/
void
cogl_depth_state_get_range (CoglDepthState *state,
float *near_val,
float *far_val);
G_END_DECLS
#endif /* __COGL_DEPTH_STATE_H__ */