Implement glReadPixels

CMakeLists.txt

@@ -37,13 +37,16 @@ add_library(${TARGET} STATIC
     src/image_DXT.c
     src/image_DXT.h
     src/opengx.h
+    src/pixel_stream.cpp
+    src/pixel_stream.h
     src/pixels.cpp
     src/pixels.h
     src/raster.cpp
     src/selection.c
     src/state.h
     src/stencil.c
     src/stencil.h
+    src/texel.h
     src/texture.c
     src/utils.h
     src/vertex.cpp

src/efb.c

@@ -41,12 +41,14 @@ POSSIBILITY OF SUCH DAMAGE.
 
 OgxEfbContentType _ogx_efb_content_type = OGX_EFB_SCENE;
 
-void _ogx_efb_save_to_buffer(uint8_t format, uint16_t width, uint16_t height,
-                             void *texels, OgxEfbFlags flags)
+void _ogx_efb_save_area_to_buffer(uint8_t format,
+                                  uint16_t x, uint16_t y,
+                                  uint16_t width, uint16_t height,
+                                  void *texels, OgxEfbFlags flags)
 {
     GX_SetCopyFilter(GX_FALSE, NULL, GX_FALSE, NULL);
-    GX_SetTexCopySrc(glparamstate.viewport[0],
-                     glparamstate.viewport[1],
+    GX_SetTexCopySrc(x,
+                     y,
                      width,
                      height);
     GX_SetTexCopyDst(width, height, format, GX_FALSE);
@@ -59,6 +61,15 @@ void _ogx_efb_save_to_buffer(uint8_t format, uint16_t width, uint16_t height,
     GX_WaitDrawDone();
 }
 
+void _ogx_efb_save_to_buffer(uint8_t format, uint16_t width, uint16_t height,
+                             void *texels, OgxEfbFlags flags)
+{
+    _ogx_efb_save_area_to_buffer(format,
+                                 glparamstate.viewport[0],
+                                 glparamstate.viewport[1],
+                                 width, height, texels, flags);
+}
+
 void _ogx_efb_restore_texobj(GXTexObj *texobj)
 {
     _ogx_setup_2D_projection();

src/efb.h

@@ -38,6 +38,10 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <ogc/gx.h>
 #include <ogc/system.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef enum {
     OGX_EFB_NONE = 0,
     OGX_EFB_CLEAR = 1 << 0,
@@ -55,6 +59,10 @@ extern OgxEfbContentType _ogx_efb_content_type;
 
 void _ogx_efb_save_to_buffer(uint8_t format, uint16_t width, uint16_t height,
                              void *texels, OgxEfbFlags flags);
+void _ogx_efb_save_area_to_buffer(uint8_t format,
+                                  uint16_t x, uint16_t y,
+                                  uint16_t width, uint16_t height,
+                                  void *texels, OgxEfbFlags flags);
 void _ogx_efb_restore_texobj(GXTexObj *texobj);
 
 typedef struct {
@@ -84,4 +92,8 @@ static inline void _ogx_efb_set_content_type(OgxEfbContentType content_type) {
     _ogx_efb_set_content_type_real(content_type);
 }
 
+#ifdef __cplusplus
+} // extern C
+#endif
+
 #endif /* OPENGX_EFB_H */

src/gc_gl.c

@@ -2611,7 +2611,6 @@ void glPushAttrib(GLbitfield mask) {}
 void glPopAttrib(void) {}
 void glPushClientAttrib(GLbitfield mask) {}
 void glPopClientAttrib(void) {}
-void glReadPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, GLvoid *data) {}
 
 /*
  ****** NOTES ******

src/getters.c

@@ -129,10 +129,16 @@ void glGetFloatv(GLenum pname, GLfloat *params)
     case GL_CURRENT_RASTER_POSITION:
         floatcpy(params, glparamstate.raster_pos, 4);
         break;
+    case GL_DEPTH_BIAS:
+        *params = glparamstate.transfer_depth_bias;
+        break;
     case GL_DEPTH_RANGE:
         params[0] = glparamstate.depth_near;
         params[1] = glparamstate.depth_far;
         break;
+    case GL_DEPTH_SCALE:
+        *params = glparamstate.transfer_depth_scale;
+        break;
     case GL_MODELVIEW_MATRIX:
         for (int i = 0; i < 3; i++)
             for (int j = 0; j < 4; j++)
@@ -173,6 +179,12 @@ void glGetIntegerv(GLenum pname, GLint *params)
     case GL_READ_BUFFER:
         *params = glparamstate.active_buffer;
         break;
+    case GL_INDEX_OFFSET:
+        *params = glparamstate.transfer_index_offset;
+        break;
+    case GL_INDEX_SHIFT:
+        *params = glparamstate.transfer_index_shift;
+        break;
     case GL_MAX_CLIP_PLANES:
         *params = MAX_CLIP_PLANES;
         return;

src/pixel_stream.cpp

@@ -0,0 +1,65 @@
+/*****************************************************************************
+Copyright (c) 2024  Alberto Mardegan (mardy@users.sourceforge.net)
+All rights reserved.
+
+Attention! Contains pieces of code from others such as Mesa and GRRLib
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+3. Neither the name of copyright holders nor the names of its
+   contributors may be used to endorse or promote products derived
+   from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL COPYRIGHT HOLDERS OR CONTRIBUTORS
+BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*****************************************************************************/
+
+#include "pixel_stream.h"
+
+const struct MasksPerType _ogx_pixels_masks_per_type[] = {
+    {GL_UNSIGNED_BYTE_3_3_2, 1, 3, 3, 2, 0, 0, 3, 6, 0 },
+    {GL_UNSIGNED_BYTE_2_3_3_REV, 1, 3, 3, 2, 0, 5, 2, 0, 0 },
+    {GL_UNSIGNED_SHORT_5_6_5, 2, 5, 6, 5, 0, 0, 5, 11, 0 },
+    {GL_UNSIGNED_SHORT_5_6_5_REV, 2, 5, 6, 5, 0, 11, 5, 0, 0 },
+    {GL_UNSIGNED_SHORT_4_4_4_4, 2, 4, 4, 4, 4, 0, 4, 8, 12 },
+    {GL_UNSIGNED_SHORT_4_4_4_4_REV, 2, 4, 4, 4, 4, 12, 8, 4, 0 },
+    {GL_UNSIGNED_SHORT_5_5_5_1, 2, 5, 5, 5, 1, 0, 5, 10, 15 },
+    {GL_UNSIGNED_SHORT_1_5_5_5_REV, 2, 5, 5, 5, 1, 11, 6, 1, 0 },
+    {GL_UNSIGNED_INT_8_8_8_8, 4, 8, 8, 8, 8, 0, 8, 16, 24 },
+    {GL_UNSIGNED_INT_8_8_8_8_REV, 4, 8, 8, 8, 8, 24, 16, 8, 0 },
+    {GL_UNSIGNED_INT_10_10_10_2, 4, 10, 10, 10, 2, 0, 10, 20, 30 },
+    {GL_UNSIGNED_INT_2_10_10_10_REV, 4, 10, 10, 10, 2, 22, 12, 2, 0 },
+    {0, }
+};
+
+const struct ComponentsPerFormat _ogx_pixels_components_per_format[] = {
+    { GL_RGBA, 4, { 0, 1, 2, 3 }},
+    { GL_BGRA, 4, { 2, 1, 0, 3 }},
+    { GL_RGB, 3, { 0, 1, 2 }},
+    { GL_BGR, 3, { 2, 1, 0 }},
+    { GL_LUMINANCE_ALPHA, 2, { 0, 3 }},
+    { GL_INTENSITY, 1, { 0 }},
+    { GL_LUMINANCE, 1, { 0 }},
+    { GL_RED, 1, { 0 }},
+    { GL_GREEN, 1, { 1 }},
+    { GL_BLUE, 1, { 2 }},
+    { GL_ALPHA, 1, { 3 }},
+    { GL_DEPTH_COMPONENT, 1, {}},
+    { GL_STENCIL_INDEX, 1, { 0 }},
+    { 0, }
+};