u_draw_quad.c revision 28486880ca3ec39419ccee0cb1a3bedc9ef7117c 
1/**************************************************************************
2 *
3 * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28
29#include "pipe/p_context.h"
30#include "pipe/p_defines.h"
31#include "util/u_inlines.h"
32#include "util/u_draw_quad.h"
33
34
35/**
36 * Draw a simple vertex buffer / primitive.
37 * Limited to float[4] vertex attribs, tightly packed.
38 */
39void
40util_draw_vertex_buffer(struct pipe_context *pipe,
41                        struct pipe_buffer *vbuf,
42                        uint offset,
43                        uint prim_type,
44                        uint num_verts,
45                        uint num_attribs)
46{
47   struct pipe_vertex_buffer vbuffer;
48   struct pipe_vertex_element velements[PIPE_MAX_ATTRIBS];
49   uint i;
50
51   assert(num_attribs <= PIPE_MAX_ATTRIBS);
52
53   /* tell pipe about the vertex buffer */
54   memset(&vbuffer, 0, sizeof(vbuffer));
55   vbuffer.buffer = vbuf;
56   vbuffer.stride = num_attribs * 4 * sizeof(float);  /* vertex size */
57   vbuffer.buffer_offset = offset;
58   vbuffer.max_index = num_verts - 1;
59   pipe->set_vertex_buffers(pipe, 1, &vbuffer);
60
61   /* tell pipe about the vertex attributes */
62   for (i = 0; i < num_attribs; i++) {
63      velements[i].src_offset = i * 4 * sizeof(float);
64      velements[i].instance_divisor = 0;
65      velements[i].vertex_buffer_index = 0;
66      velements[i].src_format = PIPE_FORMAT_R32G32B32A32_FLOAT;
67      velements[i].nr_components = 4;
68   }
69   pipe->set_vertex_elements(pipe, num_attribs, velements);
70
71   /* draw */
72   pipe->draw_arrays(pipe, prim_type, 0, num_verts);
73}
74
75
76
77/**
78 * Draw screen-aligned textured quad.
79 * Note: this function allocs/destroys a vertex buffer and isn't especially
80 * efficient.
81 */
82void
83util_draw_texquad(struct pipe_context *pipe,
84                  float x0, float y0, float x1, float y1, float z)
85{
86   struct pipe_buffer *vbuf;
87   uint numAttribs = 2, vertexBytes, i, j;
88
89   vertexBytes = 4 * (4 * numAttribs * sizeof(float));
90
91   /* XXX create one-time */
92   vbuf = pipe_buffer_create(pipe->screen, 32,
93                             PIPE_BUFFER_USAGE_VERTEX, vertexBytes);
94   if (vbuf) {
95      float *v = (float *) pipe_buffer_map(pipe->screen, vbuf,
96                                           PIPE_BUFFER_USAGE_CPU_WRITE);
97      if (v) {
98         /*
99          * Load vertex buffer
100          */
101         for (i = j = 0; i < 4; i++) {
102            v[j + 2] = z;   /* z */
103            v[j + 3] = 1.0; /* w */
104            v[j + 6] = 0.0; /* r */
105            v[j + 7] = 1.0; /* q */
106            j += 8;
107         }
108
109         v[0] = x0;
110         v[1] = y0;
111         v[4] = 0.0; /*s*/
112         v[5] = 0.0; /*t*/
113
114         v[8] = x1;
115         v[9] = y0;
116         v[12] = 1.0;
117         v[13] = 0.0;
118
119         v[16] = x1;
120         v[17] = y1;
121         v[20] = 1.0;
122         v[21] = 1.0;
123
124         v[24] = x0;
125         v[25] = y1;
126         v[28] = 0.0;
127         v[29] = 1.0;
128
129         pipe_buffer_unmap(pipe->screen, vbuf);
130         util_draw_vertex_buffer(pipe, vbuf, 0, PIPE_PRIM_TRIANGLE_FAN, 4, 2);
131      }
132
133      pipe_buffer_reference(&vbuf, NULL);
134   }
135}
136