Merge lp:~vanvugt/mir/perspective into lp:mir

[Daniel van Vugt]

GLRenderer: Add support for 3D perspective projection.

While your vertices remain at Z=0 you won't notice any change and things will
remain flat. However if you now use Z!=0 you will see 3D perspective (e.g.
render_surfaces).

[PS Jenkins bot (ps-jenkins)]

PASSED: Continuous integration, rev:1495
http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-ci/1137/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-android-trusty-i386-build/1330
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-clang-trusty-amd64-build/1328
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-trusty-touch/910
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-trusty-amd64-ci/869
        deb: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-trusty-amd64-ci/869/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-trusty-armhf-ci/874
        deb: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-trusty-armhf-ci/874/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-builder-trusty-armhf/911
        deb: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-builder-trusty-armhf/911/artifact/work/output/*zip*/output.zip
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    SUCCESS: http://s-jenkins.ubuntu-ci:8080/job/touch-flash-device/5071

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review: Approve (continuous-integration)

[PS Jenkins bot (ps-jenkins)]

FAILED: Continuous integration, rev:1496
http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-ci/1138/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-android-trusty-i386-build/1331
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-clang-trusty-amd64-build/1329
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-trusty-touch/911
    FAILURE: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-trusty-amd64-ci/870/console
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-trusty-armhf-ci/875
        deb: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-trusty-armhf-ci/875/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-builder-trusty-armhf/912
        deb: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-builder-trusty-armhf/912/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-runner-mako/853
    SUCCESS: http://s-jenkins.ubuntu-ci:8080/job/touch-flash-device/5072

Click here to trigger a rebuild:
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review: Needs Fixing (continuous-integration)

[PS Jenkins bot (ps-jenkins)]

FAILED: Continuous integration, rev:1498
http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-ci/1147/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-android-trusty-i386-build/1346
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-clang-trusty-amd64-build/1344
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-trusty-touch/926
    FAILURE: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-trusty-amd64-ci/879/console
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-trusty-armhf-ci/884
        deb: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-trusty-armhf-ci/884/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-builder-trusty-armhf/927
        deb: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-builder-trusty-armhf/927/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-runner-mako/866
    SUCCESS: http://s-jenkins.ubuntu-ci:8080/job/touch-flash-device/5105

Click here to trigger a rebuild:
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review: Needs Fixing (continuous-integration)

[Daniel van Vugt (vanvugt)]

The failure is unrelated. It's bug 1295231 again.

[Alan Griffiths (alan-griffiths)]

Nice

review: Approve

[Alberto Aguirre (albaguirre)]

LGTM

review: Approve

[PS Jenkins bot (ps-jenkins)]

review: Approve (continuous-integration)

=== modified file 'src/server/compositor/gl_renderer.cpp'
--- src/server/compositor/gl_renderer.cpp	2014-03-20 11:36:34 +0000
+++ src/server/compositor/gl_renderer.cpp	2014-03-24 02:41:17 +0000
@@ -48,7 +48,6 @@
     "void main() {\n"
     "   vec4 mid = vec4(centre, 0.0, 0.0);\n"
     "   vec4 transformed = (transform * (vec4(position, 1.0) - mid)) + mid;\n"
-    "   transformed.z = 0.0;\n" // avoid clipping while we lack depth/perspective
     "   gl_Position = display_transform * screen_to_gl_coords * transformed;\n"
     "   v_texcoord = texcoord;\n"
     "}\n"
@@ -304,10 +303,25 @@
      * (top-left is (-1,1), bottom-right is (1,-1))
      */
     glm::mat4 screen_to_gl_coords = glm::translate(glm::mat4(1.0f), glm::vec3{-1.0f, 1.0f, 0.0f});
+
+    /*
+     * Perspective division is one thing that can't be done in a matrix
+     * multiplication. It happens after the matrix multiplications. GL just
+     * scales {x,y} by 1/w. So modify the final part of the projection matrix
+     * to set w ([3]) to be the incoming z coordinate ([2]).
+     */
+    screen_to_gl_coords[2][3] = -1.0f;
+
+    float const vertical_fov_degrees = 30.0f;
+    float const near =
+        (rect.size.height.as_float() / 2.0f) /
+        std::tan((vertical_fov_degrees * M_PI / 180.0f) / 2.0f);
+    float const far = -near;
+
     screen_to_gl_coords = glm::scale(screen_to_gl_coords,
             glm::vec3{2.0f / rect.size.width.as_float(),
                       -2.0f / rect.size.height.as_float(),
-                      1.0f});
+                      2.0f / (near - far)});
     screen_to_gl_coords = glm::translate(screen_to_gl_coords,
             glm::vec3{-rect.top_left.x.as_float(),
                       -rect.top_left.y.as_float(),