tests/spec/arb_texture_buffer_object/fetch-outside-bounds.c

   1 /* Copyright © 2012 Intel Corporation
   2  *
   3  * Permission is hereby granted, free of charge, to any person obtaining a
   4  * copy of this software and associated documentation files (the "Software"),
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   7  * and/or sell copies of the Software, and to permit persons to whom the
   8  * Software is furnished to do so, subject to the following conditions:
   9  *
  10  * The above copyright notice and this permission notice (including the next
  11  * paragraph) shall be included in all copies or substantial portions of the
  12  * Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  19  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  20  * IN THE SOFTWARE.
  21  */
  22
  23 /** @file fetch-outside-bounds.c
  24  *
  25  * Tests that we can sample from outside of a texture buffer object
  26  * without crashing.
  27  *
  28  * From the GL_ARB_texture_buffer_object spec:
  29  *
  30  *     "When a buffer texture is accessed in a shader, the results of
  31  *      a texel fetch are undefined if the specified texel number is
  32  *      greater than or equal to the clamped number of texels in the
  33  *      texel array."
  34  *
  35  * we interpret this as allowing any result to come back, but not
  36  * terminate the program.  To test that, we glReadPixels the result
  37  * but don't test the values returned.
  38  */
  39
  40 #include "piglit-util-gl.h"
  41
  42 PIGLIT_GL_TEST_CONFIG_BEGIN
  43         config.supports_gl_compat_version = 10;
  44         config.supports_gl_core_version = 31;
  45         config.window_visual = PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGBA;
  46         config.khr_no_error_support = PIGLIT_NO_ERRORS;
  47 PIGLIT_GL_TEST_CONFIG_END
  48
  49 enum piglit_result
  50 piglit_display(void)
  51 {
  52         static const char *vs_source =
  53                 "#version 140\n"
  54                 "in vec4 vertex;\n"
  55                 "void main()\n"
  56                 "{\n"
  57                 "       gl_Position = vertex;\n"
  58                 "}\n";
  59
  60         static const char *fs_source =
  61                 "#version 140\n"
  62                 "uniform samplerBuffer s;\n"
  63                 "void main()\n"
  64                 "{\n"
  65                 "       gl_FragColor = texelFetch(s, 4096);\n"
  66                 "}\n";
  67
  68         GLuint tex, tbo, vbo;
  69         /* data stored in our TBO, not actually read by the shader. */
  70         static const uint8_t data[4] = {0x0, 0xff, 0x0, 0x0};
  71         uint8_t junk[4];
  72         static const GLfloat verts[8] = {
  73                 -1, -1,
  74                  1, -1,
  75                  1,  1,
  76                 -1,  1
  77         };
  78         int vertex_location;
  79         GLuint prog;
  80
  81         prog = piglit_build_simple_program(vs_source, fs_source);
  82         glUseProgram(prog);
  83
  84         vertex_location = glGetAttribLocation(prog, "vertex");
  85
  86         glGenBuffers(1, &tbo);
  87         glBindBuffer(GL_TEXTURE_BUFFER, tbo);
  88
  89         glGenTextures(1, &tex);
  90         glBindTexture(GL_TEXTURE_BUFFER, tex);
  91
  92         glTexBuffer(GL_TEXTURE_BUFFER, GL_RGBA8, tbo);
  93         glBufferData(GL_TEXTURE_BUFFER, sizeof(data), data, GL_STATIC_READ);
  94
  95         if (piglit_get_gl_version() >= 31) {
  96                 GLuint vao;
  97                 glGenVertexArrays(1, &vao);
  98                 glBindVertexArray(vao);
  99         }
 100         glGenBuffers(1, &vbo);
 101         glBindBuffer(GL_ARRAY_BUFFER, vbo);
 102         glBufferData(GL_ARRAY_BUFFER, sizeof(verts), verts, GL_STATIC_READ);
 103         glVertexAttribPointer(vertex_location, 2, GL_FLOAT,
 104                               GL_FALSE, 0, NULL);
 105         glEnableVertexAttribArray(vertex_location);
 106         glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 107
 108         glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &junk);
 109         /* We don't verify the junk read, since it's undefined. */
 110
 111         piglit_present_results();
 112
 113         return PIGLIT_PASS;
 114 }
 115
 116 void
 117 piglit_init(int argc, char **argv)
 118 {
 119         piglit_require_GLSL_version(140);
 120         if (piglit_get_gl_version() < 31)
 121                 piglit_require_extension("GL_ARB_texture_buffer_object");
 122 }