tests/general/array-stride.c

   1 /*
   2  * Copyright (c) 2011 VMware, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 /*
  25  * Test some unusual vertex array strides.
  26  * Brian Paul
  27  * June 14, 2011
  28  */
  29
  30 #include "piglit-util-gl.h"
  31
  32 PIGLIT_GL_TEST_CONFIG_BEGIN
  33
  34         config.supports_gl_compat_version = 10;
  35
  36         config.window_visual = PIGLIT_GL_VISUAL_RGB | PIGLIT_GL_VISUAL_DOUBLE;
  37         config.khr_no_error_support = PIGLIT_NO_ERRORS;
  38
  39 PIGLIT_GL_TEST_CONFIG_END
  40
  41 static const char *TestName = "array-stride";
  42
  43
  44 #define ROWS 10
  45 #define COLS 10
  46 #define NUM_VERTS (ROWS * COLS * 4)
  47
  48 static GLfloat Verts[ROWS][COLS][4][2];
  49
  50
  51 static void
  52 gen_vertices(void)
  53 {
  54    float dx = 9.0, dy = 9.0;
  55    int i, j;
  56    for (i = 0; i < ROWS; i++) {
  57       float y = i * 10.0;
  58       for (j = 0; j < COLS; j++) {
  59          float x = j * 10.0;
  60          Verts[i][j][0][0] = x;
  61          Verts[i][j][0][1] = y;
  62          Verts[i][j][1][0] = x + dx;
  63          Verts[i][j][1][1] = y;
  64          Verts[i][j][2][0] = x + dx;
  65          Verts[i][j][2][1] = y + dy;
  66          Verts[i][j][3][0] = x;
  67          Verts[i][j][3][1] = y + dy;
  68       }
  69    }
  70 }
  71
  72
  73 static void
  74 draw_simple_stride(void)
  75 {
  76    static GLushort elements[NUM_VERTS];
  77    int i;
  78
  79    for (i = 0; i < ARRAY_SIZE(elements); i++)
  80       elements[i] = i;
  81
  82    glVertexPointer(2, GL_FLOAT, 2 * sizeof(GLfloat), Verts);
  83    glEnableClientState(GL_VERTEX_ARRAY);
  84    glDrawElements(GL_QUADS, NUM_VERTS, GL_UNSIGNED_SHORT, elements);
  85    glDisableClientState(GL_VERTEX_ARRAY);
  86 }
  87
  88
  89 /**
  90  * Use a stride that's less than the vertex element size.
  91  * Use scaled indices in the element array.
  92  * Should render the same as the simple stride case above.
  93  */
  94 static void
  95 draw_unusual_stride(int stride)
  96 {
  97    static GLushort elements[NUM_VERTS];
  98    int i;
  99
 100    for (i = 0; i < ARRAY_SIZE(elements); i++)
 101       elements[i] = i * 8 / stride;
 102
 103    glVertexPointer(2, GL_FLOAT, stride, Verts);
 104    glEnableClientState(GL_VERTEX_ARRAY);
 105    glDrawElements(GL_QUADS, NUM_VERTS, GL_UNSIGNED_SHORT, elements);
 106    glDisableClientState(GL_VERTEX_ARRAY);
 107 }
 108
 109
 110 enum piglit_result
 111 piglit_display(void)
 112 {
 113    GLubyte *buf0, *buf1;
 114    enum piglit_result result = PIGLIT_PASS;
 115    int stride;
 116
 117    gen_vertices();
 118
 119    buf0 = (GLubyte *) malloc(piglit_width * piglit_height * 4);
 120    buf1 = (GLubyte *) malloc(piglit_width * piglit_height * 4);
 121
 122    /* draw reference image */
 123    glClear(GL_COLOR_BUFFER_BIT);
 124    draw_simple_stride();
 125    glReadPixels(0, 0, piglit_width, piglit_height,
 126                 GL_RGBA, GL_UNSIGNED_BYTE, buf0);
 127
 128    /* draw w/ unusual strides */
 129    for (stride = 1; stride <= 8; stride *= 2) {
 130       glClear(GL_COLOR_BUFFER_BIT);
 131       draw_unusual_stride(stride);
 132       glReadPixels(0, 0, piglit_width, piglit_height,
 133                    GL_RGBA, GL_UNSIGNED_BYTE, buf1);
 134
 135       piglit_present_results();
 136
 137       /* compare bufs */
 138       if (memcmp(buf0, buf1, piglit_width * piglit_height * 4) != 0) {
 139          printf("%s: image comparison failed at stride = %d\n",
 140                 TestName, stride);
 141          result = PIGLIT_FAIL;
 142       }
 143    }
 144
 145    free(buf0);
 146    free(buf1);
 147
 148    return result;
 149 }
 150
 151
 152 void
 153 piglit_init(int argc, char**argv)
 154 {
 155    glOrtho(-1.0, 101.0, -1.0, 101.0, -1.0, 1.0);
 156 }